The heavyweight showdown between Manchester United and Arsenal produced a suitably intense climax on Sunday as United emerged 2-0 winners to end the champions' unbeaten run one short of the half-century.

A controversial 73rd-minute penalty by Ruud van Nistelrooy and an injury-time breakaway by Wayne Rooney -- who had earned the penalty -- secured the precious Old Trafford victory.

In earlier games Newcastle United secured a last-gasp 4-3 home win over Manchester City, Middlesbrough drew 1-1 with Portsmouth and Southampton v Birmingham City ended goalless.

But the story of the day was at Old Trafford where Arsenal went down to their first defeat since losing 3-2 to Leeds United in May 2003.

They remain top of the league on 25 points, two clear of Chelsea, who beat Blackburn Rovers 4-0 on Saturday.

Everton, 3-2 winners at Norwich City, are third on 22, Bolton Wanderers fourth on 18 with Manchester United now up to fifth on 17.

United and Arsenal created little in the opening 70 minutes but the game turned when Rooney tripped over the outstretched leg of his England team mate Sol Campbell.

Van Nistelrooy, whose penalty miss in the goalless corresponding fixture last season sparked ugly on-pitch scenes, this time found the target.

Rooney completed the win - and capped a memorable 19th birthday - with a breakaway goal from Alan Smith's pass in injury time.

"I feel we were the better team...the decision of the referee made the difference," said Arsenal manager Arsene Wenger. "I feel today we were a little bit robbed."

United manager Alex Ferguson said: "It was an important victory. It's a great boost, we've been drawing too many games and hopefully we can get on a run now because we need wins to get alongside Arsenal."

AGONISING DEFEAT

It was deja vu time for Kevin Keegan at St James' Park when he saw his Manchester City team suffer an agonising last-gasp defeat at his former club.

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Newcastle fans were use to seven-goal thrillers under Keegan in the 1990s, usually going the way of the opposition, but this time it was Newcastle who took the points with an 89th-minute winner by villain-turned-hero Craig Bellamy.

Newcastle went ahead four minutes into the second half with a classic free kick by Laurent Robert and doubled the lead in the 58th minute with an Alan Shearer penalty.

City replied through Shaun Wright-Phillips after 64 minutes and made it 2-2 three minutes later when Robbie Fowler converted a penalty.

Newcastle hit back almost immediately when Robbie Elliot headed home a Robert free kick in the 69th minute only for Wright-Phillips to drill home his second five minutes later to bring City deservedly level.

Bellamy, who a week ago abused manager Graeme Souness after being substituted, this time earned his manager's praises with a well-struck 89th minute winner.

Middlesbrough, seeking their third win in eight days, did more than enough to secure it but had to be content with a draw.

Portsmouth took the lead through Senegalese striker Diomansy Kamara after five minutes.

Middlesbrough made several good chances, usually to be foiled by goalkeeper Shaka Hislop.

But it was the keeper's blunder, which eventually let them in as he allowed a low shot by Stewart Downing to squirm through his arms in the 74th minute.