An underwhelming set of results in the group phase of the revamped UEFA Champions League has left City needing to beat current holders Real Madrid to reach the last 16.
But they were razor sharp as they thrashed Salford City 8-0 in the FA Cup third round last month.
Orient’s own cup run began two rounds prior with a penalty shootout victory at non-league Boreham Wood after the game had finished 2-2 after extra time.
Goalkeeper Josh Keeley then scored an incredible 99th-minute equaliser to take their second-round match against Oldham Athletic to extra time.
Dan Agyei then atoned for an earlier missed penalty to seal the win in time added on at the end of the extra 30 minutes to send the London club through in dramatic fashion.
Wellens’ side have made a strong start to 2025, losing just one game in League One, and currently occupy the final play-off place.
He said he had told the players to enjoy the match against City, as well as trying not to bombard them with information beforehand.
“We want to make sure we put in a performance that’s as enjoyable as we can possibly make it, make it uncomfortable and try to put the pressure on them,” he said.
“[Erling] Haaland might play, but [Divin] Mubama might play, so it’s two different profile of players. [Kevin] De Bruyne might play, [James] McAtee might play so you’re not just fighting against their system and the way they’re going to play, the personnel can range as well.
“They’re all talented, they’re all brilliant players. But we’re trying to give the right balance of information to our players – we’re not overloading them too much but we’re not neglecting what we feel is the most important stuff.”