Alexis Sanchez has scored only one Premier League goal this seasonFA Cup fifth round: Chelsea v Manchester UnitedDate: Monday 18 February Time: 19:30 GMT Venue: Stamford BridgeLive coverage on BBC One from 19:00, plus live text commentary and in-play clips on the BBC Sport website and app
Manchester United interim boss Ole Gunnar Solskjaer says he is confident Alexis Sanchez's form will improve.
Chile forward Sanchez has scored five goals and struggled with injuries since joining from Arsenal in January 2018.
"We know there is a very good player there. It's like the ketchup bottle. When it comes, it comes, and I'm sure he'll be fine," said Solskjaer.
United travel to Chelsea in the fifth round of the FA Cup on Monday, a game which will be shown live on the BBC.
Sanchez opens scoring against former club Arsenal
The most recent of Sanchez's two goals this season came against Arsenal in the fourth round in January.
Signed on a four-and-a-half-year deal reported to be worth £14m a year, the 30-year-old said in an interview with BBC Sport on Saturday that he "would like to have brought more joy to the club".
Sanchez was widely criticised for his performance as a substitute in United's 2-0 home defeat by Paris St-Germain in Champions League last Tuesday.
Solskjaer won the FA Cup as a player with United in 1999 and 2004. That first cup triumph came four days before the stoppage-time winner from Solskjaer that clinched the Champions League and a historic treble.
"I'm not going to say it's the last chance because we are going to Paris to give it a go, but the chances are slimmer," said Solskjaer.
"Everyone wants to play an FA Cup final. It's one of my best memories playing at Wembley when we beat Newcastle.
"I knew I wasn't going to start the Champions League final so that was my big moment that season.
"It turned out the other way round but the FA Cup final is something we want to go to."
United are fourth in the Premier League, 14 points behind leaders Manchester City, and face PSG in the second leg of their Champions League last-16 tie on 6 March.