Cristiano Ronaldo inspired Manchester United to a 4-1 rout of Bolton Wanderers on Saturday, but their Premier League lead was kept to six points after champions Chelsea beat Sheffield United 3-0.
Ronaldo made three goals for United inside the first 25 minutes, two for South Korea's Park Ji-sung and one for Wayne Rooney, who added his second of the day before Bolton's Gary Speed converted a late penalty.
The victory, marred by an ankle injury that will sideline England defender Gary Neville for three weeks, moved United on to 75 points and a step closer to their first league title since 2003.
Chelsea are second on 69 points after a comfortable victory over the Blades following early goals from Ukraine striker Andriy Shevchenko and Ivorian Salomon Kalou. Germany captain Michael Ballack came off the bench to head the third in the 58th minute.
Struggling Manchester City got a morale-boosting 2-0 win at Middlesbrough, while Tottenham Hotspur beat relegation candidates Watford 3-1, including a goal by Spurs' England keeper Paul Robinson with a free kick from his own half.
There were 0-0 draws between Reading and Portsmouth, along with Wigan Athletic and Fulham. Blackburn Rovers were playing bottom club West Ham United in the late kickoff.
The injury to Neville, which will pose real problems for England manager Steve McClaren ahead of next Saturday's Euro 2008 qualifier against Israel, was the only cloud over an imperious performance by United -- and Ronaldo in particular.
His scintillating pace and close ball control took him to the very limit of the bye-line after 14 minutes before he deftly picked out Park for a powerful sidefoot home.
He linked up superbly with Rooney minutes later as the two forwards surged forward on the counter-attack, feeding the ball through for the England striker to dink over keeper Jussi Jaaskelainen and claim his 50th goal for United.
PARK POUNCES
Bolton's keeper could not hold a stinging Ronaldo shot shortly afterwards and Park was first to the loose ball, steering it into the gaping net.
Ronaldo got a standing ovation from the Old Trafford crowd in the 70th minute when he was replaced by Alan Smith, who promptly set up Rooney for his second of the afternoon.
The England forward rounded off the scoring with a calm finish after galloping through on the break, the early kickoff's one positive note for McClaren.
The England coach will want to ascertain the fitness of Neville's understudy in the squad, Manchester City's Micah Richards, who limped out of their win over Boro in the first half.
Paying tribute to Ronaldo, Ferguson told Sky Sports News: "His season has been incredible, you can't put one game in front of another as far as I'm concerned because he's given his all in every game.
"Today, particularly in the second goal, the combination between him and Wayne Rooney -- and his weighted pass to Wayne to finish things off -- was tremendous."
Chelsea coach Jose Mourinho was also pleased with his side after their demolition of Sheffield United, who never recovered from Shevchenko's excellent opener in the fourth minute.
Mourinho was stoical about matching United's win, telling Sky Sports News: "They do their job, we do our job.
"The only thing we have under our control are our matches -- and we can believe that if we win them, we might recover three points."
Victory for Manchester City after a run of five league defeats will be a real boost for under-pressure manager Stuart Pearce, whose side had played well in a 1-0 midweek defeat by Chelsea.
French defender Sylvain Distin and Belgian striker Emile Mpenza, with his first for the club, were the goalscorers for a delighted Pearce, who said: "It's all about character at this stage of the season."
Along with England goalkeeper Robinson, whose booming free kick bounced over England understudy Ben Foster, Spurs' goals came from Jermaine Jenas and Egyptian Hossam Ghaly.