Cristiano Ronaldo's controversial penalty gave Ralf Rangnick a second successive Premier League win as Manchester United claimed an unconvincing 1-0 victory at Norwich City.

United laboured for long periods at a sodden Carrow Road but were given a chance to break an unexpectedly long deadlock when Max Aarons was adjudged to have pulled down Ronaldo.

The Portugal forward stepped up to convert the spot-kick 15 minutes from time, his emphatic finish proving the difference despite a spirited effort from the league's bottom club.

United are fifth, level on points with fourth-placed West Ham but with an inferior goal difference, while Norwich remain three points adrift of safety.

Alex Telles saw a free-kick deflected onto the crossbar, but United struggled to break down the division's leakiest defence in the first half and were frustrated by Tim Krul in the Norwich goal.

Ronaldo was thwarted by a diving save from the Dutchman while Harry Maguire saw a header tipped over in the closing stages of the first 45 minutes.

Norwich provided more of an attacking threat in the second half and only a flying save from David de Gea prevented Teemu Pukki from firing the opener into the top-left corner.

But they were left aghast when Darren England pointed to the spot despite Ronaldo appearing to go down easily under contact from Aarons.

There was no doubt about Ronaldo's effort from 12 yards, which he lashed into the bottom-left corner – two stunning saves from De Gea to deny Ozan Kabak and the kind of United defending that was often lacking during Ole Gunnar Solskjaer's tenure ensuring it was enough for all three points.