West Ham 2-4 Man Utd

Wayne Rooney scored a second-half hat-trick as Manchester United came back from 2-0 down at West Ham to open up an eight-point lead at the summit of the Premier League.

Sir Alex Ferguson's men looked to be facing a repeat of their Carling Cup reverse at the hands of the Hammers as Mark Noble's pair of penalties put the home side in command at the break as they looked to climb away from the drop zone.

But Rooney, who is finding his form again at a crucial stage, clearly had other ideas and he rattled off a 15-minute treble of the highest quality before substitute Javier Hernandez accepted the gift of a fourth six minutes from time.

United started well and put the Hammers on the back foot in the opening stages without creating any clear-cut openings, with Chris Smalling's header from a corner being pushed over by Rob Green before Michael Carrick blazed well off target.

But with virtually their first attack of the game West Ham took the lead in the 11th minute as Thomas Hitzlsperger's long ball out of defence picked out Carlton Cole, with the striker's attempt to loft the ball over Patrice Evra blocked by the full-back's hand.

Referee Lee Mason pointed to the spot on the advice of his assistant and Noble made no mistake as he stepped up to coolly send Tomasz Kuszczak the wrong way from 12 yards with a confident low effort.

United immediately looked for a response and went close when Rooney's low cross was missed by a diving Park Ji-Sung at the near post before Ryan Giggs' follow-up effort was deflected behind for a corner.

But they were soon 2-0 down due to more defensive deficiencies, with Cole again earning the spot-kick as he bamboozled Vidic on the edge of the box before being tripped by the Serbia international.

Mason again pointed to the spot despite more futile United protests and Noble this time beat Kuszczak with a powerful effort into the top corner of the net which gave the Red Devils shot-stopper no chance.

Park thought he had reduced the deficit on the half-hour mark as he fired goalwards with real power from 14 yards out, but Green showed excellent reflexes to dive and divert the South Korean's effort over the bar.

United may have felt they were wronged with the penalty decisions, but they arguably enjoyed a slice of fortune five minutes before the interval when Vidic hauled down Demba Ba with the striker threatening to burst clear, but only saw yellow despite being the last man, although Kuszczak's position may have influenced Mason.

Hitzlsperger attempted to curl the resulting free-kick over the wall and into Kuszczak's near post, but saw his effort fly narrowly the wrong side of the post with the goalkeeper scrambling across.

Ferguson made a change at the interval, with striker Hernandez replacing left-back Evra and veteran midfielder Giggs slotting into the back four, and the duo combined within 40 seconds for the Mexican to fire narrowly over.

United continued to search for an equaliser without truly threatening Green, and a second switch was made in the 64th minute with leading scorer Dimitar Berbatov thrown into the fray in place of Park.

The languid Bulgarian had only just trotted on to the surface when Rooney halved the deficit with a stunning curling free-kick from the edge of the box which swerved around the West Ham wall before nestling in Green's net after Noble felled Carrick.

Berbatov went close with an individual effort which Green kept out at his near post, but the England international could do nothing to keep out another sublime strike from Rooney in the 73rd minute.

The striker took Valencia's pass away from the covering Hammers defenders with his first touch before firing a low strike across Green and into the far corner of the net before celebrating in front of the ecstatic visiting fans.

And he completed an astonishing turnaround from the spot with Upson very harshly penalised for handball when Fabio's attempted cross struck his arm from less than a yard away, stroking into the bottom corner to claim his hat-trick.

With West Ham now pushing to get back on terms, they left gaps at the back, which gave Giggs the time and space to drill in a cross-shot, which was missed by Upson on the six-yard box allowing a grateful Hernandez to slide home.

United's success piles the pressure on Arsenal, who host Blackburn later in the day, while West Ham have slipped back into the bottom three on goal difference.