Erik ten Hag has admitted Andre Onana needs to "step up", but urged the summer signing to take confidence from some of Manchester United's previous goalkeepers.
Onana arrived at Old Trafford in the summer for £47million as he replaced David de Gea as the club's number one, with the Spaniard leaving at the end of his contract.
It has been a poor start to life in England for Onana, who was fortunate not to concede a penalty on his Premier League debut against Wolves and has made a number of errors since then.
Speaking ahead of his side's trip to face Sheffield United this weekend, Ten Hag made it clear Onana has to improve, but the United boss insisted he has full confidence that will happen.
"He knows [he's not been good enough], we know, he will do much better," Ten Hag said.
"As with every player who's coming into the Premier League, you need an integration period but he has to step up. Big United keepers like Peter Schmeichel and David De Gea started [slowly] and Andre knows that it is good to know a little bit from history.
"We live now, we live in the future and he has to make his future by giving better performances. I'm sure he will do.
"He showed it at Barcelona, Ajax, Inter Milan, he was in the semi-final and the final of the Champions League, I'm sure he will give a great performance."
Ten Hag was though less keen to discuss Jadon Sancho, who remains out-of-favour at United
The winger has not played since coming off the bench against Nottingham Forest in August, and has been exiled from first-team training. A January exit looks likely, with neither Ten Hag or Sancho appearing to have any desire to back now.
"Everything has been said about that," Ten Gag said on Friday.
