MANCHESTER, England (AFP) - Manchester United strengthened their English Premier League lead with a 3-0 win at Old Trafford over arch-rivals Liverpool, who had to play more than half the game with 10 men.

Late goals from Cristiano Ronaldo and Nani added gloss to Wes Brown's first half-opener against a Liverpool side who, after going a goal behind, then saw Javier Mascherano sent off just before half-time.

Brown opened the scoring in the 34th minute before Mascherano was given a second booking by referee Steve Bennett, for showing dissent.

United failed to build on their lead for much of the second-half but Ronaldo's 34th goal of the season followed by Nani's strike gave them a convincing win in a game they had shaded from the start.

United opted to play Wayne Rooney as a lone striker and the England international should have opened the scoring after five minutes.

Anderson threaded the ball through but Jamie Carragher's challenge put Rooney off balance and he shot straight at Jose Reina.

Two minutes later Brown's quickly-taken free-kick saw Rooney beat the offside trap but the striker could not control the ball.

Liverpool were comfortable in possession but were creating next to nothing and again it was United's turn to threaten again midway through the first-half as Ronaldo touched Ryan Giggs's deep free-kick onto the post.

Liverpool finally went close when captain Steven Gerrard's powerful strike was deflected narrowly wide by Nemanja Vidic from Dirk Kuyt's clever lay-off.

But just over 10 minutes before the interval, United took the lead.

United defender Brown cut out Fabio Aurelio's clearance and continued his run forward as the ball was played to the left by Paul Scholes.

Rooney crossed and, with Martin Skrtel failing to challenge as Reina flapped, the ball flew in off Brown.

But the game really exploded into life a minute before half-time.

Fernando Torres was chopped down by Paul Scholes but the referee booked the Spain striker for dissent near the touchline.

Mascherano also came across to question the official and was shown a second yellow card, with Xabi Alonso and Liverpool coach Alex Miller having to prevent him from confronting Bennett.

Rafael Benitez also attempted to calm the midfielder before he became embroiled in a row of his own with United assistant manager Carlos Quieroz.

Ronaldo should have doubled the lead a minute after the restart but failed to test Reina after Scholes chipped over the Liverpool defence.

Anderson wasted another great chance with just under 20 minutes left, slicing over after fine work by Rooney.

Carlos Tevez almost scored with his first touch but Reina pulled off a fine one-handed stop after the Argentinian striker prodded goal-wards after the ball deflected off Alvaro Arbeloa.

Ronaldo was wasteful again after Tevez chested Brown's cross into his path, with Reina turning onto the bar from close-range.

But from the resulting corner, Alonso left the Portuguese midfielder alone and he rose unmarked to head in Nani's cross, with Reina again nowhere near the ball after coming off his line.

And two minutes later, Nani made it three by collecting Rooney's pass and cutting across the Liverpool defence before hitting the corner of the net from 20 yards to seal on what could be a key victory for Sir Alex Ferguson's men.