Cristiano Ronaldo ended his goal drought in emphatic style as Manchester United moved up to fourth in the Premier League table with a 2-0 win over Brighton at Old Trafford.

Ronaldo had gone six games without scoring but blasted home before Lewis Dunk’s red card dented Brighton’s hopes and Bruno Fernandes’ strike effort added late gloss to the score.

“It was a good performance by Ronaldo,” said Man Utd interim manager Ralf Rangnick. “In the last few weeks, it was certainly the best performance by him and a very, very important goal.”

It was anything but a convincing performance from United overall, Jakub Moder hitting the crossbar and Danny Welbeck somehow heading over after Brighton were down to 10 men.

Indeed, it had required a spectacular save from David de Gea just to keep his side on level terms at the break, clawing away a Moder header with his outstretched right hand.

Brighton produced the more enterprising football in that first half with United reliant on counter-attacks, the best chance coming the way of Jadon Sancho early on.

But the game turned on two losses of possession in their own half, Ronaldo punishing Yves Bissouma’s mistake and Dunk fouling Anthony Elanga after his own poor touch.

The win – only United’s third in seven games – lifts Ralf Rangnick’s side two points above West Ham and into the Champions League qualification places. Brighton remain ninth.

Ralf Rangnick made two initial changes to the team that drew at home to Southampton. Anthony Elanga came in for Marcus Rashford, while Fred replaced Paul Pogba in midfield. A third was forced on him minutes before kick-off with Victor Lindelof stepping up for the ill Raphael Varane.

Graham Potter made three changes to the Brighton team that beat Watford. Yves Bissouma, Alex Mac Allister and Leandro Trossard came in for Tariq Lamptey, Adam Lallana and Danny Welbeck.

Ronaldo could have added to his tally in the second half. Twice he failed to punish Brighton with his head – once thanks to a fine save by Robert Sanchez and then when he sent his attempt wide. He was unselfish when setting up Fernandes in the second half too.

The bigger concern for Rangnick will be that his team were outplayed before the red card. In terms of coherent possession play, there was little sign of the revolution taking shape. Fred endured a miserable night in midfield and Brighton’s passing game looked superior.

What Manchester United possess are those decisive players and Rangnick will at least be buoyed that the pressing game was on point – both goals and the Dunk red card all coming after winning the ball back from the opposition. That will be the encouraging aspect of this. But there is much work to do to claim that fourth spot in May.

Under the spotlight after a dip in form, Ronaldo made the difference. It was an error that presented him the ball with space to run into but there are few players who would have been so ruthless with that chance. It was the moment that changed the night.

“We get punished from a world-class finish by a world-class player,” said Potter afterwards. “That is what we are facing.”

Ronaldo tends to play in moments now but he had a few here. He could easily have had assists after setting up clear-cut chances for both Sancho and Fernandes.

After a run of games in which Manchester United have led at half-time and then failed to win, this was a very different match. This time, the game turned in United’s favour in the second half – and that was a result of a tactical change by Rangnick at the interval.

“Everyone could see after the first half, it was not an easy game,” he explained. “They are very possession-based. It was difficult for us to get hold of the ball. We made a change and it paid off. In the second half, we were more aggressive and tried to intercept the ball.

“The question at half-time was do we change formation or how we attack. We decided to stick to 4-2-3-1 and told our wingers to attack their centre-backs. That meant our full-backs had to jump to their full-backs and that paid off. From then on, it was a different game.”