Manchester United interim manager Ralf Rangnick slammed his side's shoddy first-half performance after a flattering 3-1 victory away to Brentford in the Premier League on Wednesday.

The German also had to deal with a Cristiano Ronaldo tantrum after substituting the Portuguese forward in the second half.

Lacklustre United were outplayed by Brentford in the first half and were indebted to keeper David De Gea but goals by Anthony Elanga, Mason Greenwood and Marcus Rashford capped a much-improved second-half display.

It was a vital win for United and keeps them in the thick of the battle for a top-four finish, but Rangnick was not impressed by what he saw in the opening 45 minutes.

"You have to be honest, without David and his brilliant saves it would have been difficult," Rangnick told reporters.

"We were sloppy in our passing, not strong enough in the tackles, losing the 50-50 challenges and didn't win a single second ball. When we did counter-attack we were too nervous. (Reuters)

•PHOTO: Rangnick