Wayne Rooney scored one goal and superbly set up another as Manchester United overwhelmed Middlesbrough to move to the top of the Premier League.
Rooney scored his eighth goal in seven games
United went ahead on three minutes when Nani drove in a cracking shot from 30 yards but Jeremie Aliadiere soon equalised with a precise header.
Nani robbed Stuart Downing and played in Rooney, to smash United's second.
After the break Carlos Tevez slotted in after a sublime Rooney back-heel and he added a fourth with a deflected shot.
United scored four goals in a fourth successive game - the first time in 100 years they have done so.
They knew a win would see them overtake leaders Arsenal - at least until Sunday when the Londoners play Liverpool.
And the hosts, who had Owen Hargreaves in their starting line-up for only the fourth time, wasted no time in setting about their task.
Nani decided to take the direct approach after picking the ball up deep in Boro's half. He skipped two challenges as he cut inside and then launched a dipping shot from 30 yards which beat Mark Schwarzer for height and pace.
It was a dream start for United but a nightmare for Boro, who went into the game desperately short of confidence after failing to win in their previous six matches.
And the visitors still appeared shell-shocked when Tevez broke through the middle but the Argentine did not quite get his attempted lob right and Schwarzer made a comfortable catch.
The script appeared set - a rampant United, with Nani and Ronaldo rampaging down the flanks and Rooney menacing through the middle about to rip through woeful opposition.
But Tuncay clearly felt a re-write was in order and promptly delivered the perfect cross - after turning stand-in left-back John O'Shea inside-out - for Aliadiere to head into the bottom left corner.
It was Aliadiere's first goal for Boro and it served to galvanise them. For the next 10 minutes, Boro held their own as United's early fluency deserted them.
The visitors even missed a great chance to take the lead as frequent threat Tuncay crossed in for Downing to head just wide of the right hand post.
Still, you felt once United smoothed out their now-stuttering approach play, Boro could find themselves in trouble once more.
And so it proved, as Ronaldo went close with a low shot from the left side of the box as United slipped through the gears.
Then Downing tried to trick his way past Nani on the edge of his area but had the ball nicked from his toes and played into the path of Rooney who smashed the ball home.
For the rest of the half, it seemed it was a matter of time before United scored again, particularly through Ronaldo.
But the Portuguese winger could not convert Nani's cross and later side-footed straight at Schwarzer after a slick passing move.
Immediately after the break, Rooney fizzed a drive just too high and wide and once more it seemed United were about to turn the screw.
Middlesbrough might have prevented it had Edwin van der Sar not been equal to Lee Cattermole's rising shot.
But after Rooney produced an exquisite backheel for Tevez to slot the ball into the bottom corner on 55 minutes, the contest was over.
Ronaldo started to stretch his legs again, twisting and turning the Boro defence but not finding a finish to match.
United took off Hargreaves for Darren Fletcher on 66 minutes, and later took the chance to give Rio Ferdinand an extended rest ahead of next Sunday's visit to Arsenal.
It barely affected the pattern of the game, although Boro almost cut United's lead when Downing went close with a curling free-kick.
But instead, Tevez rounded things off for United with 15 minutes to go when his shot looped off Andrew Taylor and beat a disconsolate Schwarzer.
It was the fourth match in succession they had scored four goals - equalling a record which stretched back to 1907.
Manchester United assistant manager Carlos Quieroz:
"Boro made it difficult for us, they came back well to make it 1-1.
"We expect to start the game with a lot of quality and enthusiasm, and usually when we do that the game becomes easier. That was not the case today.
"But we regained out composure, first touch and movement and we started to control things and deserved the win."
Middlesbrough manager Gareth Southgate:
"We wanted to come here and have a go. We scored and created a couple of good chances.
"Today was a shot to nothing. In the end their class told. But for a long time in the first half it was tight.
"We had a very young side and sometimes mistakes will happen. But our young players were outstanding today and they are a shining light."
Man Utd: Van der Sar, Brown, Ferdinand (Pique 73), Vidic, O'Shea, Ronaldo, Hargreaves (Fletcher 66), Anderson (Giggs 78), Nani, Rooney, Tevez.
Subs Not Used: Kuszczak, Simpson.
Goals: Nani 3, Rooney 33, Tevez 55, 85.
Middlesbrough: Schwarzer, Young, Woodgate, Wheater, Taylor, O'Neil, Cattermole (Boateng 90), Rochemback, Downing, Aliadiere (Hutchinson 56), Sanli (Lee 80).
Subs Not Used: Turnbull, Hines.
Booked: Cattermole, Rochemback.
Goals: Aliadiere 6.
Ref: Alan Wiley (Staffordshire).