Belgium had to come from two goals down to beat Japan 3-2 in Rostov-on-Don and will now face Brazil after a stunning comeback.
Five-time champions Brazil are widely tipped as favourites to win a sixth crown and Benteke is already cranking up the pressure on Neymar and his team.
Despite being left out of the Belgium squad after a poor Premier League season with Crystal Palace, Benteke saw the chance to poke fun at Brazil by using snaps of former Liverpool team-mate Philippe Coutinho.
Indeed, one picture sees Coutinho smiling, with the caption: "When you think you'll play Japan in the quarters." And it sits next to another, with Coutinho grimacing, with the words "But Belgium turns it around with a last minute winner."
Whether or not his social media antics come back to bite him later, with Belgium facing Brazil on Friday in Kazan, remains to be seen.
Brazil beat Mexico 2-0 in their quarter-final, with Neymar and Roberto Firmino both on the scoresheet.
When you think But Belgium turns— Christian Benteke (@chrisbenteke) July 2, 2018
you’ll play Japan it around with a
in the quarters last minute winner pic.twitter.com/rmQA2wWBlu