Sunderland 0 Manchester United 4: Alex Ferguson re-asserted his authority over talismanic former skipper Roy Keane as Manchester United maintained the pressure on Arsenal.

United cruised to a 4-0 victory at the Stadium of Light to leave Keane in little doubt as to the gulf in class between the teams at opposite ends of the Premier League.

United's victory was every bit as comfortable as the scoreline suggests as they cut through the Black Cats at will to expose goalkeeper Craig Gordon at regular intervals.

Goals from Wayne Rooney, Louis Saha and Cristiano Ronaldo before the break left the result in no doubt, and Ferguson was even able to withdraw the hugely impressive Portugal international with more than half an hour remaining.

Saha rubbed salt into the wound with an 86th-minute penalty after Nani had been tripped by Danny Collins.

United headed back across the Pennines having reached the mid point of the season firmly in the title race, while the man who for more than 12 years led their charge for glory on the pitch has just 14 points in the bag and a long haul towards safety.

Keane knows the bulk of his side's points this season will not be taken from the likes of United, Arsenal, Chelsea and Liverpool, but from the sides in the battle for top-flight survival.

However, having seen them compete creditably in narrow defeats at both Old Trafford and the Emirates Stadium already, that was the very least he expected at the Stadium of Light today.

What he got in the opening 45 minutes was graft and commitment, but what his players lack was abundantly clear as United, despite barely getting out of second gear, took them apart so comprehensively that damage limitation was the
only thing on the minds of the bulk of a crowd of 47,360.

Rooney set the ball rolling on 20 minutes when, after full-back Brown had played a one-two with Ronaldo, he slid the striker in to fire nonchalantly past Gordon.

Rooney turned provider 10 minutes later, accepting Ronaldo's pass from the United half before cutting inside Wallace to pick out Saha at the near post.

But it was the Portugal international who set the seal on a blistering start when he smashed home an injury-time free-kick with Gordon rooted to the spot.

The was a brief glimmer of hope for the home side when Michael Chopra's enterprising run set up Dickson Etuhu to shoot on 51 minutes, but he skied his effort harmlessly over.

Ronaldo departed to warm applause from both sets of supporters a minute later with his job done as Park Ji-Sung was handed his first taste of first-team action since undergoing knee surgery in March.

The home side rallied as the clock ran down, but with the visitors in cruise control, genuine openings were few and far between.

Chopra saw a 75th-minute shot beaten away by Kuszczak, but it came either side of another Gordon save from Rooney and an uncharacteristically wild close-range volley from the United man.

There was, however more to come, and when Nani went down under Collins' challenge, referee Uriah Rennie pointed to the spot and Saha obliged.