The 31-year-old suffered the blow and was forced from the field after coming off the bench during his side's Europa League semi-final first-leg victory over Celta Vigo.
Jose Mourinho's side could have left Spain with more to show for their efforts, but once again they were left to rue their inability to kill games off.
The Reds boss said afterwards the tie is still "open".
"Last year we scored three goals away against Atletico Madrid to go through (in the Copa del Rey) and their defence is very strong, and this year we won 2-1 at the Bernabeu and they are nearly in the Champions League final". It overcame a 1-0 loss at home in the round of 32 to Shakhtar Donetsk, and advanced by 2-0 win in the second leg. Celta also defeated Real Madrid away from home in the Copa del Rey, and eventually eliminated Madrid.
Manchester United teenager Marcus Rashford can cope with pressure and will only get better, according to team-mate Jesse Lingard. I think we're happy with the 1-0.
'It is still close, it is half-time, they are leading 1-0 and we have to go out and make the second-half count.
"We have confidence in the fact our attack is freed". It's a good result away and we're in a good position.
On the second leg, Berizzo added: "We are going to play a game having learned what happened tonight".
United sit fifth in the Premier League ahead of a trip to Arsenal on Sunday.
"We know we can do it", he emphasized. "We created chances in the first half and we deserved the goal".
United's Spanish midfielder Ander Herrera, who hails from the northern Basque region of Bilbao, urged caution though and stressed that Vigo remain a unsafe side ahead of the second leg.
"Martial was fresh and he had to give us these last 10-15 minutes where we thought we still could score".
Speaking to BT Sport after the game, Pogba said: "On the pitch, we don't look at the age".
"We tried to win the match but we missed chances. But the opposition was hard, the match was hard, the stadium was hard, so I can not be happier with the players and their work".
United midfielder Ander Herrera hailed the defence for keeping a clean sheet on the night. But the former Manchester City player believes his side were denied a chance to get back into it.