But Cristiano Ronaldo's 67th- minute penalty miss will be seen as a big reason why the champions slumped to a shock 1-2 defeat at West Ham yesterday.

Goals by defenders Anton Ferdinand and Matthew Upson gave the home side the win, after Ronaldo himself had put United ahead.

The loss was only United's third in the top-flight campaign, and will have given their title rivals renewed hope, reported the BBC.

West Ham's fans had booed their side at the end of the last home game when the Hammers drew 1-1 with Reading on Boxing Day.

But they vociferously supported their team at the start, and their efforts almost reaped immediate dividends.

Lucas Neill sent a dipping shot just wide, before the Hammers worked a glorious opening.

Hayden Mullins was slipped in on goal by Carlton Cole's clever touch, but he angled his shot on to the crossbar as he tried beating on-rushing United goalkeeper Tomasz Kuszczak.

The ball rebounded to Mark Noble and he looked certain to slot into a gaping net, only to sidefoot high.

United quickly punished the home side with ex-Hammer Carlos Tevez, who was applauded at the start, beginning the attack on the halfway line.

He held on to possession to drag right-back Neill out of position before finding Louis Saha.

Saha released Giggs into the space created by Tevez down United's left flank and the Welshman crossed for Ronaldo to nod in at the near post on 14 minutes.

The goal briefly winded West Ham, before they recovered as the game turned into a captivating contest.

The home side were pushing for a leveller and United were a constant threat on the counter-attack.

Nolberto Solano had a curling 25-metre strike tipped over the bar by Kuszczak, while Giggs would have been clean through at the other end had his normally assured touch not let him down.

Hammers striker Cole had started ahead of Dean Ashton and he was found in space by Noble's cross but headed over.

Ronaldo dragged a shot wide of the near post just before a half which the Hammers ended the stronger.

But West Ham's main problem was their lack of ruthlessness in the final third, with United's meagre defence also standing firm like so many times this season.

Solano and Scott Parker were forced off injured for West Ham shortly after the break as United took the sting out of their play.

And the game should have been put out of the home side's reach after 66 minutes when the ball struck makeshift centre-back Jonathan Spector's arm after he mistimed a dive to meet a cross.

Ronaldo stepped up to take the spot-kick - only to power his strike wide.

The miss breathed new life into West Ham and their crowd and they produced a rousing finale.

Anton Ferdinand equalised against his brother Rio's side from a Noble corner on 77 minutes.

Upson then rose highest on 82 minutes to head a winner from a Noble free kick into the top corner.

The home side then held on for only a third home win of the season.

Upton Park erupted as the race for the Barclays Premier League title took another dramatic twist.