Manchester - Jose Mourinho said "enemies" were undermining his team after Paul Pogba was injured in a 1-0 victory over FC Rostov that sent Manchester United into the Europa League quarter-finals.
Pogba, who turned 24 on Wednesday, hobbled off with a hamstring injury early in the second half of Thursday's 1-0 win, which completed a 2-1 aggregate last 16 success.
United had previously played on Monday, losing 1-0 at Chelsea in the FA Cup quarter-finals after going down to 10 men, and travel to Middlesbrough in the Premier League on Sunday.
In an apparent reference to United's domestic fixture schedulers, Mourinho complained: "We have lots of enemies. Normally the enemies should be Rostov, but we have a lot of enemies.
"It's difficult to play Monday with 10 men. It's difficult to play now. It's difficult to play 12 o'clock on Sunday. We have a lot of enemies."
Mourinho said Pogba would be out for around three weeks, ruling him out of the trip to Middlesbrough and France's forthcoming games against Luxembourg and Spain.
Asked if Pogba would be out for around three weeks, Mourinho replied: "Yeah. I don't know for sure, but for sure, no Middlesbrough and no national team."
Warming to his theme, Mourinho suggested the compression of matches meant United were likely to lose at struggling Middlesbrough, who on Thursday sacked his former Real Madrid assistant Aitor Karanka.
"A lot of people might say we should have scored more goals. But a lot of things are going against us," he told BT Sport at Old Trafford.
"The boys are amazing boys. We will probably lose the game on Sunday. Fatigue has a price. I will remember forever when I spoke to the UEFA delegate in Rostov.
"He told me if any of our players gets injured, the insurance paid. Whoever decided the Monday and Sunday games probably thinks the same way."
In a curious scene, Mourinho was seen relaying a banana to Argentine centre-back Marcos Rojo during the second half, which the United manager said was an attempt to combat fatigue.
"If you were tired any time in your life, I was tired many times, I know what the body needs," said the Portuguese.
"It needs anything. The player asked for a banana. But it's not to laugh at all. It's to respect the players."
France star Pogba departed in the 47th minute after pulling up as he chased an opponent towards the halfway line, with Marouane Fellaini taking his place.
United prevailed on the night thanks to a 70th-minute goal by Juan Mata, who finished from close range after Zlatan Ibrahimovic had flicked Henrikh Mkhitaryan's cross towards goal.
United, who have never previously won the Europa League, will discover their quarter-final opponents in Friday's draw.
Russian club Rostov came close to taking the game to extra time late on, with United goalkeeper Sergio Romero obliged to save from substitute Aleksandr Bukharov and Christian Noboa.
"It's another historic game for us," said beaten manager Ivan Daniliants, whose side had never previously gone so far in European competition.
"We played against one of the best teams in the world. They were obviously stronger, but we fought until the end. We're thankful to our fans for their support."