We're finding our rhythm, says Sir Alex

As Cristiano Ronaldo was left bloodied following an elbow to the forehead, Rooney cut through Roma's defence in the 71st minute.

Hail the heroes: Rooney scored the winner for United

And while Rooney was taking out Roma, Robin van Persie was Arsenal's goal hero as the Premier League leaders became the first English club to win at Steaua Bucharest.

United manager Sir Alex Ferguson last night predicted that Rooney is about to fire his team to top form as they recorded their sixth 1-0 victory of the season.

The win was barely deserved and came largely because the Italians, beaten 7-1 on the same ground last season, failed to convert a number of chances.

Ferguson was, though, willing to admit to a certain amount of relief at the Italians' profligacy.

"I was relieved. I think it would have been unfair but then football can be unfair," the United manager said of Roma's missed chances.

"I think we deserved that bit of luck because we played with good control, good football, good tactical awareness, so I was pleased with the performance."

Ferguson added: "It's been difficult for Wayne because he's had an injury and he's just trying to find his true form. It's only his fourth match back and it is always difficult.

"But we are beginning to play some better football and find some rhythm and I have no worries about Wayne."

Ronaldo was substituted near the end of the game with blood pouring from a head wound which required four stitches.

Blood and thunder: Ronaldo receives some running repairs

He was adamant he had been the victim of a deliberate elbow by Roma's Mirko Vucinic. Ferguson added: "I haven't seen the incident on TV but Cristiano thought it was deliberate.

"It's a shame because, on the whole, it was a game played in great spirit and refereed very well. Both sets of players deserve a tremendous amount of credit."

Roma coach Luciano Spalletti believed his team should have had a penalty after United's Michael Carrick tangled with the Brazilian Mancini in the second-half.

Spalletti said: "It was a definite foul but there is nothing I can do now."

Arsene Wenger was delighted with Arsenal's victory and said: "It was not the most glamorous game. It was a good team display and the team is hungry."

Arsenal thought they had won the game without Van Persie's close-range effort in the 75th minute because TV showed that Steaua goalkeeper Robinson Zapata had carried a deflected Gael Clichy cross over the line in the first half.

Rangers recorded arguably the best European result in their history by winning 3-0 at Lyon in Group E. They next face Barcelona, who also made it two wins out of two by beating Stuttgart 2-0 in Germany.