Jose Mourinho's substitutions in the second-half of Manchester United's defeat at Basel killed the visiting team's momentum and played a role in their eventual downfall on Wednesday, 22 November, according to former Everton striker Tony Cottee.
United needed only a point at St Jakob-Park to secure progress to the Champions League knockout stages, and dominated proceedings in the first half, with captain Paul Pogba dictating play from midfield.
However, the Frenchman was replaced shortly after the hour mark with Nemanja Matic, with Basel progressively growing in confidence towards the closing stages of the game.
Michael Lang then evaded the attentions of Daley Blind to convert Raoul Petretta's cross in the 89th minute to hand the visitors their first defeat in the Champions League this season.
"It was possibly a mistake to take Pogba off, he was probably their best player," Cottee told Sky Sports.
"Mourinho made changes and brought on Marcus Rashford, Nemanja Matic and Zlatan Ibrahimovic, but Pogba was the one in midfield who was making things happen.
"They did lose the midfield in the last 20 minutes, but United should have had the game wrapped up [by that point]."
United will progress to the Champions League knockout stages if they avoid a seven-goal defeat against CSKA Moscow at Old Trafford, and Cottee said he obviously expects the Red Devils to qualify.
"It's a devastating result for Manchester United," he said. "They could have got the point or won the game and coasted through the last game of the group. But now they've got to put in a professional performance [against CSKA].
"Tonight's result should not make any difference in terms of qualification, with the CSKA game at home. They should go through now, with a point certainly enough."
Meanwhile, former United defender Rio Ferdinand accused the Red Devils of taking Basel too lightly.
"It's what you wouldn't really associate with a Jose Mourinho team and that's lacking professionalism," Ferdinand was quoted as saying by ESPN.
"I think second-half, they lacked that discipline."