The Kenyan-based betting firm, which also has a partnership with the Gunners, sent the message to "the fans of Everton Football Club", part of which read:
"We owe you an apology.
We have to be honest in admitting that the tweet you saw yesterday should never have gone out and we are deeply sorry for any offence this has caused. We have reviewed and will revise our internal policies and processes, especially in relation to our other partner clubs, to ensure that this never happens again.
"The sentiment behind the tweet is not reflective of SportPesa or our staff. When we signed out partnership with Everton Football Club it was one of the proudest moments in our history. Our relationship with Evertonians and the people of Merseyside means so much to us.
"We are truly very sorry."