Ole Gunnar Solskjaer says Manchester United’s fixture schedule over the coming week is “physically impossible” after his side reached the Europa League final.
United lost 3-2 to Roma but emerged 8-5 aggregate winners in the semi-final and will now meet Villarreal on 26 May.
Thursday’s game in Rome was the first of four matches in eight days.
“It’s unheard of,” said Solskjaer after reaching his first final as United boss.
Speaking for the first time since learning United will have to play league games on Sunday, Tuesday and next Thursday, Solskjaer added: “It’s made by people who have never played football at this level.
“It’s physically impossible for the players.
“We are going to need everyone for these four games. It’s a short turnaround but we have to be ready.”
United, who are second in the Premier League, are away to Aston Villa on Sunday (14:05 BST).
Their home match with Liverpool, postponed on Sunday after about 200 fans broke into Old Trafford to protest against the Glazer family’s ownership of the club, has been rearranged for Thursday, 13 May (20:15).
The decision means United must play two games in the space of 50 hours as their home game against Leicester has been moved forward a day to Tuesday, 11 May (18:00).
United also host Fulham on 18 May and finish their league campaign at Wolves on 23 May before heading for Gdansk, Poland, to play Villarreal.
‘It feels good to make it to a final’
Solskjaer, a Champions League winner with United as a player, can look forward to his first final since taking charge of the club after Jose Mourinho was sacked in 2018.
United had lost their previous four semi-finals under the Norwegian but they advanced at the fifth attempt thanks mainly to their 6-2 first-leg win at Old Trafford last week – and an excellent goalkeeping display by David de Gea in Rome.
“It feels good to be in the final,” added Solskjaer. “We played one very good half at Old Trafford which has taken us through. I’m disappointed we’ve lost this game.
“It was a strange game. We kept giving them the ball but luckily we have one of the the best keepers in the world. We are in the final and are looking forward to 26 May.”
‘It was like basketball’
In an extraordinary semi-final which produced 13 goals over both legs, United captain Harry Maguire described the second leg in Rome as being like “basketball”.
Edinson Cavani extended United’s aggregate lead before former Manchester City forward Edin Dzeko equalised on the night.
Bryan Cristante put Roma ahead only for Cavani to make it 2-2, substitute Nicola Zalewski scoring the winner after a deflection.
“It’s a great achievement to get to the final,” said Maguire. “We didn’t win the game and that’s disappointing but we did the hard work in the first leg.
“We started the game a bit edgy. It was end to end like basketball and we gave them too many chances in second half.
“Now we’ve got to go to the final and win it. Edinson scored two great goals and his movement and work-rate without the ball is excellent.
“His second goal is typical of him and what he has done throughout his career.”