Jose Mourinho told Manchester United's underachieving players to "stay at home" if they cannot handle the pressure to perform at Old Trafford.
Young Boys are the visitors on Tuesday evening as the Red Devils look to reach the Champions League last 16 with a game to spare - a feat they will achieve should they win and Valencia fail to beat Juventus.
Progress would be a welcome shot in the arm after Saturday's tepid goalless draw with struggling Crystal Palace, which left them 14 points behind Premier League leaders Manchester City and with a mere three wins from nine home matches in all competitions.
However, Mourinho knocked back suggestions his players find it easier to play away and laughed off a suggestion that playing at Old Trafford brought added pressure ahead of facing the Swiss champions.
"If you feel pressure to play matches at home where the people come to support... come on.
"I never felt pressure to play at home."
Mourinho expects a response from his side in Tuesday's Group H encounter, having questioned some of his players' "heart", desire and intensity after the 0-0 draw with Palace.
The United manager stopped short of using such cutting soundbites on the eve of the Young Boys encounter but shed a light on the issues he faces.
"It's frustrating because what I want is the team to start strong, is the team to go strong on the opponent, not to be waiting, not to be reactive but proactive," Mourinho said, having also said his side are "not very good on second balls".
"That's exactly what I want and probably you or the fans, they think 'oh, Jose told them to start slow', 'Jose told them to play nice and easy and wait to see what happens' or 'to be losing for then to react'.
"It is exactly the opposite thing. I want the team to start strong, I want the team to have a go immediately and it is a bit frustrating."
Frustrating would also aptly describe Victor Lindelof's injury setback.
Recently crowned Sweden's player of the year, the improving 24-year-old has established himself as one of the first names on the team sheet.
But Lindelof's resurgence after a slow start to life at United has been derailed by a muscle issue, meaning Mourinho's remaining centre-back options are Chris Smalling, Eric Bailly and Phil Jones.
Marcos Rojo - yet to play a minute this term - is also absent for the United manager, who has made his frustration clear at the club's failure to reinforce the defence over the summer.
"(Lindelof) does the scan (Tuesday) but, by the experience of the medical department and the feelings of the player, he has a muscular problem and a muscular problem takes time," added Mourinho, who said Lindelof would be out for "quite a while".
"I would say if we have him for the Christmas period - where we need, if possible, every player to be available for that difficult period until the Newcastle match on January 2 - if we can have Victor available for that period, it will be good."