Wayne Rooney finally broke his 18-game Champions League drought but there was very little else for 10-man Manchester United to cheer as their Treble hopes suffered a setback in the Stadio Olimpico.

Paul Scholes' dismissal for two yellow cards after just 33 minutes had left the Red Devils in trouble against Roma.

For a brief period after Rooney had coolly levelled Taddei's first-half strike, it appeared United would complete their mission with spectacular success.

But substitute Mirko Vucinic bundled home the rebound after Edwin van der Sar had failed to hold Mancini's blistering shot to earn Roma a richly-deserved victory.

At least Sir Alex Ferguson got the away goal he demanded but the United boss knows his side, lacking the suspended Scholes, will have to do better in the return leg on Tuesday to stand any chance of progressing to the last four.

Ferguson had promised every tactical angle would be covered as United attempted to reach the semi-finals for the first time since 2002.

In terms of shackling dangermen Francesco Totti and Mancini, the visitors largely got it right.

Unfortunately, they failed to heed early warnings about Roma's liking for quickly-taken corners and eventually paid the price.

Van der Sar might have fancied his chances of keeping out Taddei's effort. But once it flicked off Wes Brown and Gabriel Heinze, the giant Dutchman had no chance.

It was a goal Roma definitely deserved but unfortunately, it sparked ugly scenes in the stands where, for the second United European away-day running, riot police were called in to quell disturbances.

The confrontations lasted well into the interval and did not bode well for the remainder of the evening.

Apart from their team going behind, United's 4,000-strong travelling support were also taking in the fact their team had been totally outplayed and were down to 10 men following Scholes' dismissal.

Never the best tackler, the former England star had already ruled himself out of the Old Trafford return by flying into Christian Wilhelmsson on the halfway line.

When he then stuck out a leg to halt Totti's advance, German referee Herbert Fandel had little alternative other than to brandish a second yellow card.

The dismissal just gave Roma even more licence to attack. Totti brought a couple of good saves out of van der Sar, then Taddei did the same to earn the corner that eventually led to his goal.

In fact, with Cristiano Ronaldo and Rooney completely snuffed out and Ole Gunnar Solskjaer making little impact either after being handed the central striker's berth, about the only thing that went right for United in the opening period was the booking Simone Perrotta picked up for diving under Heinze's challenge when the tie was still level.

It must have been particularly disappointing for Perrotta, one of three World Cup winners in the hosts line-up, as it ended his hopes of an emotional return to the city of his birth, having been raised in Ashton-under-Lyne before his parents returned to Italy when he was a child.

The Roma onslaught continued once the game restarted but, with Perrotta twice failing to add to the home side's tally, there must have been some lingering suspicion within the Roma camp that a nasty shock was awaiting them.

And so it proved too as Ronaldo finally escaped the shackles of Roma's rigid defence and found Solskjaer with a superb pass.

The Norwegian instantly lifted a far-post cross to Rooney, who gleefully lashed home his first Champions League goal since his debut-day hat-trick against Fenerbahce in September 2004.

For a few short minutes, an unlikely victory appeared on the cards, with Solskjaer bringing a good save out of Doni as United pressed.

But it proved to be a brief renaissance as Roma quickly regained the initiative after van der Sar could only beat away Mancini's powerful drive, allowing substitute Vucinic to force home the rebound.

It was all defensive hands to the pump for the visitors after that.

Perrotta's shot deflected wide off Brown, then the midfielder rasped another just over before Totti flashed a long-range effort just wide when van der Sar appeared to be beaten.

Heinze was needlessly booked for too much backchat, although at least the visitors were able to run the clock down and escape with a single-goal defeat when it could - and should - have been worse.

Teams

Roma Doni, Panucci, Mexes, Chivu, Cassetti,Wilhelmsson (Vucinic 62), Taddei (Rosi 82), De Rossi, Perrotta,Mancini, Totti.

Subs Not Used: Curci, Faty, Defendi, Ferrari, Okaka Chuka.

Booked: Perrotta.

Goals: Taddei 44, Vucinic 67.

Man Utd Van der Sar, Heinze, Ferdinand, O'Shea, Brown,Ronaldo, Giggs (Saha 77), Carrick, Scholes, Rooney,Solskjaer (Fletcher 72).

Subs Not Used: Kuszczak, Smith, Dong, Richardson, Eagles.

Sent Off: Scholes (34).

Booked: Scholes, Solskjaer, Heinze.

Goals: Rooney 60.

Att: 77,000

Ref: Herbert Fandel (Germany).