The Red Devils beat their Belgian opponents 2-1 at Old Trafford, 3-2 aggregate, to progress to the last four of the competition, with 19-year-old forward Marcus Rashford scoring the winner in extra-time.
Rooney, who has only been a bit part player for Jose Mourinho’s side this season, was an unused sub with the manager deciding to bring on Anthony Martial when veteran forward Zlatan Ibrahimovic got inured late in the game.
Keane told ITV after the game on Thursday: “In terms of the bigger picture I’d have thought that’s the end of Wayne at Manchester United.
“He will obviously contribute until the end of the season because of injuries.
“But he must be fuming not to be brought on. I think that’s the final nail in the coffin for him, definitely.
“Leading scorer at the club, I’d expect him to be fuming, if he’s not fuming then he’s obviously lost the eye of the tiger. He must be like a mad man tonight, he must be.”
Catch all the 2018 FIFA World Cup action, and the FIFA U-20 World Cup 2017, LIVE on Kwesé Sports. Get Kwesé TV now in Ghana, Zambia or Rwanda. To enjoy our streamed free channels, viewers all over Africa can download the Kwesé App for iOS or Android or register online.