Cristiano Ronaldo [Images] scored a stunning injury-time goal against his former club to give Manchester United a 2-1 win over Sporting and a guarantee of top spot in Champions League Group F on Tuesday.

The Portugal winger, who had scored United's winner in Lisbon in September, repeated the feat with a perfectly-struck free kick from 25 metres into the top corner. The goal secured United's fifth win from five in the competition.

Sporting, who are assured of a UEFA Cup slot, had led through a 21st-minute goal from Abel and threatened to hand United only a second defeat in 33 home European games.

But United dominated the second half and substitute Carlos Tevez equalised in the 61st minute, before Ronaldo scored a goal he had promised to deliver all night.

United are top on 15 points, five clear of AS Roma who beat Dynamo Kiev 4-1, with one game left to play.

Ronaldo returned to the United side after the 22-year-old had been rested for last Saturday's shock Premier League defeat by Bolton Wanderers.

His selection was one of six changes made by manager Alex Ferguson but right from the start the outcome appeared to revolve around Ronaldo.

RONALDO STYLE

Though he had been apologetic about celebrating his decisive goal in Lisbon, it did not stop him turning on the style on a night when many of his team mates were below par.

United had started in near exhibition mode as Ronaldo went through his full repertoire of tricks.

Not all of them came off and at times he would have been better to do the simple things right, although one clever flick did create a chance for French forward Louis Saha, who dragged his shot wide on a rare starting appearance.

Sporting took the lead just two minutes later when an attempted cross from defender Abel flew past a badly positioned Tomasz Kuszczak and inside the near post.

The goal filled the visitors with hope and moments later Liedson was only fractionally offside when he controlled an intended shot from Anderson Polga and drilled the ball home.

With United's response lacking any urgency or conviction, Ferguson sent on both Tevez and Ryan Giggs, his only two attacking substitutes, at the start of the second half.

Tevez equalised within 16 minutes with his sixth goal of the season and second in as many Champions League games as he diverted a Ronaldo shot past keeper Rui Patricio.

Tevez then created a chance for Ronaldo but his low shot was saved by Patricio as the Sporting goal came under increasing pressure.

Ronaldo was far more effective than before the break and he sent a chip inches wide of the target before Owen Hargreaves almost scored with his first touch in European competition for United.

Patricio came to Sporting's rescue, saving with his feet, but was then powerless to stop Ronaldo taking centre stage with almost the last kick of the game as he lashed a right-foot shot into the net.