Juan Mata admits Manchester United go into their rearranged final Premier League game with a bad taste in their mouths after missing out on a top four spot.
United needed neighbours City to lose their last game at Swansea on Sunday to have any hope of claiming a spot in the Champions League.
But City drew 1-1 at the Liberty Stadium meaning that, barring an improbable 19-0 win over Bournemouth at Old Trafford tonight, United will have to make do with a place in the Europa League.
Consequently the Bournemouth clash, which was called off on Sunday because of a bomb scare, now has little riding on it for United.
They could still climb above Southampton from sixth to fifth but the players' attention may already been turning to Saturday's FA Cup final against Crystal Palace.
Midfielder Mata said: "We will have to close the Premier League season on Tuesday. It's going to be a bittersweet farewell to Old Trafford, now that we know we won't be playing the Champions League next season.
"It leaves us with a bad taste because, even if we enjoyed good moments together throughout the season, we weren't consistent enough to qualify for the top European competition.
"It's true that we found many difficulties along the way, especially if we talk about injuries (up to 15 players in several weeks, as far as I remember), but Manchester United must be ambitious and always fight for everything."
Events at Old Trafford on Sunday, which saw the stadium evacuated in a full-scale security alert, took attention away from speculation over United manager Louis van Gaal's future.
Van Gaal has been under heavy scrutiny for most of the season and there have been reports his position was dependent on whether United reached the top four or not.
It remains to be seen whether tonight now proves to be his final game at Old Trafford or whether he continues, or if the FA Cup final may yet have a bearing.
Victory for Bournemouth, whose first season in the top flight has been a success, would lift them two places to 14th.
Van Gaal may now field a different side from that intended as he prepares for Wembley, but midfielder Marouane Fellaini is suspended.
Fans who were at Old Trafford for the original game on Sunday have been offered a refund and free entry to the rescheduled fixture, a gesture that it is estimated will cost the club £3million.
Mata also spoke of the shock he and fellow players experienced as Sunday's clash with Bournemouth was abandoned over security concerns.
Old Trafford had to be evacuated shortly before kick-off after a suspect device, later revealed to be a fake bomb not removed after a training exercise, was discovered in toilets at the stadium.
The item was destroyed by bomb disposal experts while the game - both clubs' final Premier League fixture of the season - was called off and rearranged for tonight.
The players were warming up on the pitch when the evacuation of the stands began.
The Spanish midfielder added: "What happened in Old Trafford this Sunday left all of us who were there absolutely shocked.
"Everybody in the security team did an effective job, resulting in a quick evacuation of the stadium.
"It helped not to spread panic around, although all of us had a very odd feeling; something like strain mixed with a lack of understanding.
"The fans left the stadium before we did. I think we left Old Trafford at around 5pm, with the feeling that everything was already under control.
"I feel sorry for all those people who had to go back home without watching the game, because that's what they had come for.
"Obviously, safety is always the top priority but what I'm really sorry about is that this kind of issue affecting football, sports and society in general.
"Many of us think that sport has the capability to unite people, and we must keep believing that."