Ronaldo was sent off for an apparent headbutt on Portsmouth substitute Richard Hughes in a dramatic last few minutes at Fratton Park - just seconds after Portsmouth's Sulley Muntari was dismissed for a second bookable offence.

Although the Portuguese player faces a three-match ban for violent conduct, Manchester United manager Sir Alex Ferguson may be even more worried that his champions are going into Sunday's Premier League derby against City still seeking their first competitive win in five games - and four points behind Chelsea.

Benjani Mwaruwari's second goal in two games - a bullet header after 52 minutes - wrecked their hopes of victory after Sunday's home draw with Reading.

They are, of course, also without the injured Wayne Rooney, whose absence allowed Carlos Tevez to make his United debut.

Although the Argentinian's talent looked to be slightly wasted in a lone-striker role Tevez played a significant part in the opening goal by Paul Scholes and almost snatched a late winner.

Nani, the Portuguese youngster bought in a combined £30million deal with compatriot Anderson, made one of a series of left wing forays on his own full debut and fed the ball into Tevez - who turned and set it up perfectly for Scholes to blast in from 15 yards on the quarter-hour mark.

The goal galvanised United into more positive action after a fairly pedestrian start and Pompey were happy to see Ronaldo's shot deflected into the side-netting for a corner soon afterwards.

But their hastily-reconstructed defence was beginning to creak against a growing pressure of attacks from the Red Devils and Ronaldo was twice close to breaking through again before the interval.

Yet Pompey had a lively attacker in John Utaka, whose goal almost brought them victory at Derby on Saturday, and a strong midfield presence in Muntari.

And although James had to make thrilling saves at the start of the second half to defy both Nani and Tevez, they stormed back into the game with Benjani's dramatic equaliser seven minutes after the break.

The late dismissals scarred what was a much better second half but Pompey finished celebrating another against-the-odds triumph.

They had beaten United in three of their previous four visits to Fratton Park and well deserved the point.