The controversial moment came just hours after City had pipped their rivals Liverpool to the post and claimed the Premier League title.
And if that wasn't bad enough, the wrestler decided to go one step further and serenaded the crowd with a reworked version of the Beatles' classic, 'Yesterday'.
As a cacophony of boos rang around the arena, Elias, who was sat on a stool and wearing his WWE 19 replica strip, sang: "Earlier today, Man City won their biggest game. Now Liverpool has no more games to play."
Elias shocked the crowd when he put on a City strip with 'WWE 19' across the back. Credit: WWE
Then, referencing Liverpool's upcoming Champions League final match with Tottenham Hotspur, he said: "Except when they lose to the Spurs two weeks away."
The pretty brilliant piece of trolling was then shared by the WWE from their official Twitter account, with the caption: "Note to self @iameliaswwe: In the home of The Beatles, you probably shouldn't rewrite the lyrics to their hit song "Yesterday" or wear a certain team's jersey! #WWELiverpool."
Even Manchester City shared the clip, writing: "Sounds like the @fans in Liverpool are getting a bit shirt."
And pretty happy with his evening's work, Elias then tweeted: "It is often said that the loudest a crowd can possibly get on any given night.. that sound.. that volume.. Elias is responsible for that."
Fans were quick to praise his ballsy move.
Boos echoed around the arena as he broke into his version of 'Yesterday'. Credit: WWE
One fan wrote: "What absolute bastardry, WWE hold an event in Liverpool just a few hours after the Premier League had come to a close. Elias wears a Manchester City shirt!"
A second said: "I have a lot of time for Elias trolling Liverpool fans in WWE's Liverpool event tonight."
A third fan put: "Absolute top class trolling from WWE superstar Elias here. Pulling on a Manchester City jersey at an event in Liverpool the very evening after City pip Liverpool to the title. Superb heel work there."
While another added: "I hate both teams but what Elias did was absolutely genius, the man is great at getting underneath the fans' skin."
"Top, top shithousing by Elias at WWE live, wearing a city champions shirt on stage & singing about Liverpool losing. Absolute uproar, love it," wrote yet another impressed viewer.
Despite beating Wolves 2-0 on the final day of the season, Liverpool weren't able to close the gap on rivals City and finished the season on 97 points, just one behind the blues.
They will get one more shot at silverware on 1 June, when they play Tottenham in the final of the Champions League.
Featured Image Credit: WWE