Harry Redknapp watched from the stands as Manchester United came from behind to beat his new Queens Park Rangers side at Old Trafford.QPR, who announced Redknapp as their new boss on Saturday morning, led when Jamie Mackie pounced from close range.Headers from Jonny Evans and Darren Fletcher, on his first league start for over a year, put United in command."In the end a not-unexpected scoreline but for an hour Manchester United were off-key as QPR made a real go of it. But three goals in eight minutes turned the game around for Manchester United."Substitute Javier Hernandez stroked in the third as Sir Alex Ferguson's men moved top of the Premier League table.United's three goals in the space of eight second-half minutes puts the pressure firmly back on neighbours Manchester City, who know they can return to the summit by beating Chelsea on Sunday.QPR, who sacked Redknapp's predecessor Mark Hughes on Friday, stay bottom of the table as they remain without a victory in their opening 13 matches.But there will be plenty of positives for Redknapp to take from the match before he assumes control on Monday.Under the guidance of Hughes's former coaches Mark Bowen and Eddie Niedzwiecki, the hard-working visitors refused to allow United any space and used their compact defensive unit as a base to catch their hosts on the break.Scotland international Mackie was the focal point of QPR's counter-attacking raids and he thought he had put them ahead just before the interval when he sent a diving header past United goalkeeper Anders Lindegaard.But the goal was correctly ruled out for offside, with replays showing Mackie had strayed ahead of United central defenders Rio Ferdinand and Evans.It was a laboured performance from the hosts in the opening hour, as Ferguson's side allowed their opponents to score first for the ninth time in 13 top-flight matches this season.A shock looked to be on the cards as Mackie struck after Lindegaard could only parry Kieron Dyer's low cross into his path.United had been rather pedestrian up to the goal and it served to wake them from their slumber as Ferguson urged his players to increase the tempo of their play.Wayne Rooney, back in United's starting XI after missing the last two matches with tonsillitis, pushed further forward alongside Robin van Persie in a bid to stretch a QPR backline that had already conceded 23 goals this season.And it was the England striker who provided the spark for United's recovery. His left-wing corner was met at the far post by Danny Welbeck, whose header allowed Evans, also making his return from injury, to score from virtually on the goal-line.Moments later, Fletcher swung the match in United's favour - again from a Rooney corner.The Scotland international, whose last Premier League appearance came on 19 November 2011 before he missed the rest of the season with a bowel complaint, found space in the QPR box to head in.Hernandez sealed victory as he raced on to a throughball from fellow substitute Anderson before confidently slotting past Hoops goalkeeper Julio Cesar.Manchester United boss Sir Alex Ferguson:"We only played for 10 minutes and those 10 minutes were brilliant. The crowd got up and I thought Anderson changed the game for us."We expected an improved performance from QPR, it always happens when a side loses their manager. They fought very hard and had some good counter-attack play."Falling behind again is a concern but it was a wake up call. Then we got down to our business and played with speed and determination. Victories like this when you're not really at your best are always important."Darren Fletcher has had a long journey back and he has showed he is back to his best."