There are still five days left in the transfer window a long time by footballing standards and plenty could still happen to cause another twist in the John Stones saga, but tonight's pulsating tie at Oakwell might have been a transformative one in some respects for Everton, the player and Roberto Martinez.
Fewer than 48 hours since news broke that he had submitted a transfer request, there were no guarantees that the manager would name Stones in the squad to face his old club at the stadium where he cut his teeth. But in the absence of any official word from Everton regarding the player's decision, Martinez delivered something of a statement by including him in the starting XI. Under the pressure of the spotlight, the 21-year-old may not have enjoyed his most convincing performance but he came through 120 minutes on the right end of a 5-3 scoreline, was applauded warmly off the field by the vast majority of the 4,300 Blues amassed in the away end, and was spoken of in undeniably supportive terms by his gaffer to the television cameras after the game.
Martinez's disdain for Chelsea's media-driven pursuit of his young protege and the lack of support from "the authorities" was as unmistakable as his instinct to protect Stones and if the player's decision to signal an intent to leave Everton after just two and a half years and 48 appearances was in any way a personal choice, his manager might have given him plenty of food for thought over where is best for him as he continues his development as the club prepare to formally reject that request for a transfer.
For Martinez, just days after coming under criticism from supporters for his unimaginative substitutions against Manchester City, his half-time changes proved to be spot-on as Gerard Deulofeu and Ross Barkley came off the bench to inspire a fightback and an overall attacking performance that eventually booked Everton's passage to the third round.
The Spaniard had, of course, made a belated and very rusty-looking cameo at the end of Sunday's defeat but here, given a 45-minute run-out one that ultimately stretched to 75 minutes against more favourable opposition, his impact was game-changing. Though McGeady had tried gamely enough to influence proceedings, he wasn't able to ruffle the Tykes' back line in quite the same way as Deulofeu, while the injection of Barkley's own direct running and driving from midfield offered a greater attacking dimension once Tom Cleverley had dropped into a right-back role in place of debutant Matthew Pennington.
Pennington had actually done fairly well in the first half but thanks to the kind of indecisive defending that is becoming more common under Martinez from some of the more experienced heads, he was an obvious candidate to be sacrificed with the score at 2-0 to Barnsley. There is something to the argument that you should play your strongest line-up or a minimally-changed team, at least but against League Two opposition, Martinez clearly felt it was a calculated risk to include some players who were some way off full match fitness. His decision was ultimately vindicated but it owed much to the attacking talent he has assembled and nurtured in his two years at Goodison Park.
Things had looked routine enough in the early going, though Josh Scowen had had the first real sight of goal for hosts when he bounced a shot narrowly wide of Joel Robles' right-hand post. Everton had largely assumed control of the match by quarter-hour mark and really should have been a goal to the good already but Aiden McGeady contrived to shoot meekly at goalkeeper Ben Davies with the goal at his mercy after the ex-Everton Academy goalkeeper had parried Mirallas's shot into his path.
Nevertheless, with Mirallas buzzing around behind the front line and Cleverley knitting things together in midield, it seemed just a matter of time before the superior attacking unit made the breakthrough. Instead, it was Barnsley who scored mid-way through the first half. Stones failed to properly deal with a low cross from the left and Jagielka was similarly indecisive leaving Sam Winnall free to fire the loose ball into the far corner of the goal from about 12 yards out.
Matters got worse when the Tykes doubled their lead in the 28th minute. The decision to field the second-string goalkeeper for League Cup ties has come back to bite Everton in the past and the spectre of a selection-related cup disaster loomed when a deep cross to the back post was headed back across goal and Robles fluffed his lines with Marly Watkins in attendance and the ball ended up in the net off the Barnsley man.
With their manager stone-faced on the sideline, the Blues needed a rapid response but they would be frustrated by opposition defenders who put their bodies on the line to keep shots from Lukaku and Muhamed Besic from troubling Davies, while the 'keeper made a routine save to keep out McGeady's tame attempt to curl a shot past him.
Based on the scoreline, a major upset was on the cards at the half-time interval but you got the sense that Everton would still have too much for Barnsley if they could get their attacking unit clicking. It took just six minutes of the second half for the Blues to put that theory to the test when Oviedo's cross came off a defender's arm and fell invitingly to Mirallas who rocketed a half-volley past Davies.
And after Deulofeu had seen a rather scuffed effort saved by Davies and Barkley had steered a header off the rebound well wide, Everton levelled the game in the 59th minute. More great work by Deulofeu in the cramped environs near the corner flag with two red shirts for company ended with a cross that found Naismith beautifully in the centre and the Scot headed powerfully home from close range.
That should have been the platform from which the Premier League side went on to put the tie to bed but they were caught cold less than 60 seconds later as Oviedo battled to contain Watkins down the Barnsley right and he eventually delivered a low cross that Dan Crowleuy swept home with a tidy first-time finish to restore the Tykes' lead.
Deulofeu's probing almost forced Marc Roberts into prodding into his own net under the attentions of Lukaku but the ball was hacked off the goal line and the referee somehow ignored pleas for a stonewall penalty when Watkins put his arm across across Oviedo face and sent him sprawling as he raced onto Mirallas's pass on the overlap.
But Martinez's men did draw level again when another excellent delivery by Deulofeu from near the touchline picked out Lukaku's run and the Belgian side-footed home to make it 3-3.
A victory in normal time would elude the Blues but it certainly wasn't for the want of trying as they racked up chances in the final stages. Barkley rattled a shot inches wide and the skied a decent chance high into the stand, Lukaku saw a driven shot cannon off Reece Wabara's shoulder and behind for a corner, Jagielka almost converted a Deulofeu cross with a reaching header, Mirallas glanced a Lukaku centre a foot wide and Deulofeu chipped the final chance agonisingly over Davies's crossbar.
Barnsley's valiant stand was broken in extra time, however, although it remained an open contest throughout the additional half an hour as legs tired and mistakes crept in. Indeed, Robles was the first of the two goalkeepers to be tested when he spilled a powerful shot but was rescued by a blue-shirted defender before Deulofeu did prompt Roberts into inadvertantly finding his own net, again with Lukaku hovering menacingly. Had the defender not stabbed the ball in, the Belgian would have done but, regardless, it was 4-3 on the night.
Still, while Everton failed to kill the Tykes off by wasting terrific opportunities on the break-away Mirallas and Naismith getting in each other's way when either would almost certainly have scored was the most glaring instance Lee Johnson's men remained in with a chance but they fell agonisingly short from their perspective when Connor Hourihane with an impressive curling shot from distance that no doubt had Robles's heart in his mouth as it sailed past him.
One of those counter-attacks finally did pay for the Blues five minutes from the end as Barkley romped forward and then held his pass until Lukaku was set ahead of him and he released the striker for a simple side-foot finish past the stranded 'keeper to make it 5-3.
Lukaku steers home to make it 5-3
There was still time for Lukaku to grab his hat-trick but he unselfishly tried to tee up Barkley or Deulofeu and his cut-back caught the heels of a defender and the chance was lost.
They had done it the hard way but the job had been done, however, and Martinez can now prepare for a third-round date at Reading next month. It must be said that Barnsley's performance belied their status among England's third tier and they pushed their more fancied top-flight opponents all the way in an entertaining tie but, in the end, Everton had too much firepower, partcularly when Deulofeu was introduced.
It was a game that will hopefully have provided Martinez with something to ponder when it comes to the permutations across his forward line. Deulofeu clearly added what had been so criminally lacking against City at the weekend namely, width while the combination of the Spaniard and Mirallas operating in concert with Lukaku and Barkley provides an explosive attacking unit with the right defensive formation behind it.
The manager was reluctant to operate with two wingers for much of last season and it was reflected in his team's struggles to break teams down; whether this evening re-opens his eyes to those possibilties again remains to be seen but it's clear that he has weapons at his disposal if he can use them correctly while shoring up a defence that remains prone to mistakes.
How curious is the hand of fate that Everton should be facing Barnsley when they kick off their League Cup campaign. The Tykes have been prominent in the Toffees' recent history with two of their homegrown defenders completing transfers to Goodison Park and while Mason Holgate could make a quick return to his former stomping ground, big question marks hang over the appearance of John Stones following his decision yesterday to hand in a transfer request.
What would have been a glorious homecoming for one of the Yorkshire club's best graduates will either not happen at all or it will take place under a swarm of headlines and the glare of media attention. That choice will fall to Roberto Martinez as he and the Everton hierarchy presumably weigh up how to handle the 21-year-old's request to be allowed to leave before Tuesday's transfer deadline.
Assuming Stones's mind has been made up for some time and he has been biding his time to see if Everton would bow to one of Chelsea's three bids to date for his services, he has been remarkably composed in his three appearances so far this season and has betrayed few effects of the attention it has garnered or the dilemma he has been facing.
Whether he will still be in the right frame of mind to play in this second-round tie is another matter but Martinez, having waited until the last week of the window to sign a replacement for one of Antolin Alcaraz and Sylvain Distin, finds himself worryingly short of options at the back.
Phil Jagielka is the only other senior centre half at the club and Brendan Galloway, a more than capable deputy on the evidence thus far, is almost certain to be ruled out with the knee injury that forced him off against Manchester City on Sunday. That leaves Tyias Browning and Holgate as the remaining choices if the manager doesn't consider dropping Gareth Barry to centre half.
Thankfully, with Bryan Oviedo lined up to make his first start since February, Martinez has a natural replacement for Galloway at left back but the rest of his team selection will, by his own admission, allow some of the players who haven't featured much thus far to get some game time. That is likely to mean opportunities for players like Leon Osman, Gerard Deulofeu and, perhaps, Arouna Kone, Kevin Mirallas and Conor McAleny. There are also likely to be places for some of the U21s squad on the substitute's bench as Martinez balances squad-rotation with the need to progress in one of the two most likely routes to silverware this season.
A sizeable chunk of the Evertonian fanbase will be uncomfortable with anything other than a strong line-up this evening, however. Putting maximum focus on winning a trophy and, in particular, a competition that Everton have never won has become a priority for many supporters.
Indeed, it's a competition that has been unkind, even painful, to the Blues in its 55-year history and not since winning away at Hull six years ago has an Everton side won an away tie in the League Cup. A match against a League One side should be routine for a Premier League side, however only one top-flight team was beaten in last night's fixtures so let's hope it will be the Toffees and not the Tykes making the trip to Reading next month in the third round.