After Manchester City had thrashed Aston Villa 5-0 earlier in the afternoon, only a win would have been enough for United to jump over their neighbours once again.
However, with England striker Wayne Rooney missing because of tonsillitis, the Red Devils produced a lacklustre display as the Canaries - reborn since the international break - produced another composed display to secure a third win in five Premier League games with a fine header from Anthony Pilkington on the hour.
At the Etihad Stadium, David Silva scored the opener for City from close range just before half-time while Sergio Aguero scored from the penalty spot after Ciaran Clark handled the ball in the area.
Carlos Tevez added City's third from the spot when Barry Bannan was also adjudged to have handled the ball before Aguero fired his second of the game.
Tevez did the same to cap of a resounding resounding win for the defending champions and they end the day leading the pack.
City are now four points ahead of Chelsea, who slumped to a 2-1 defeat against West Brom at the Hawthorns.
Shane Long opened the scoring in the 10th minute before Eden Hazard equalised for Chelsea on the stroke of half-time.
However, Peter Odemwingie headed past Petr Cech from Long's assist to earn the Baggies another impressive win.
In the lunchtime kick-off, a moment of madness from Emmanuel Adebayor sparked a spectacular Tottenham collapse as Arsenal romped to a 5-2 victory in an entertaining north London derby at the Emirates Stadium.
Adebayor scored against his former employers to give Tottenham a 10th-minute lead, but he pressed the self-destruct button seven minutes later when he was given a straight red for a horrific sliding tackle on the excellent Santi Cazorla.
Tottenham struggled to cope with the numerical disadvantage thereafter and it only took a few minutes for Per Mertesacker to equalise.
Lukas Podolski's strike, and Olivier Giroud's fifth goal in his last five games gave Arsenal a comfortable two-goal cushion by half-time.
Tottenham fared slightly better in the second half, but their only reward came through a Gareth Bale consolation after Cazorla killed the contest.
To add insult to injury Theo Walcott grabbed a deserved goal in injury time to make the score the same as the 5-2 win that Arsenal used as a springboard for their Champions League assault last season.
Arsenal's victory means they jump above Tottenham in the table, while Spurs have now suffered four successive defeats under Andre Villas-Boas, who will have questions to answer about why he decided to play Adebayor if there were doubts about whether the striker could keep a lid on his emotions.
Goals for Rickie Lambert and Jason Puncheon helped to seal a vital 3-1 win for struggling Southampton against QPR at Loftus Road .
Lambert headed in from close range before Puncheon added the second from 20 yards, with Junior Hoilett's second-half header not enough for Mark Hughes' side, as Anton Ferdinand's own goal in the 83rd minute compounded QPR's woes.
Luis Suarez scored a brace as Liverpool beat Wigan 3-0 at Anfield.
The Uruguay international beat Ali Al Habsi twice in the second half with strikes from the middle of the area as Liverpool moved closer to the top half of the table, with Jose Enrique's tap-in sealing the win for Reds boss Brendan Rodgers.
Reading came from behind to earn their first Premier League win this season with a 2-1 win over Everton at the Madejski Stadium.
Poor defending by Reading allowed Steven Naismith to open the scoring for the Toffees before Adam Le Fondre marked his return to the Royals side by equalising with a glancing header.
Everton's Seamus Coleman then conceded a penalty which Le Fondre duly converted to earn a much-needed three points for coach Brian McDermott.
Elsewhere, Swansea beat Newcastle 2-1 at St James' Park thanks in part to a blunder by Magpies keeper Tim Krul.
Krul miscued a clearance straight to Pablo Hernandez, who picked out Michu with a great cross, allowing the Spaniard to head the ball past Krul and into the net.
Jonathan de Guzman sealed the win late in the game when he followed up substitute Danny Graham's blocked strike with Demba Ba's stoppage time score not enough for Newcastle.
Saturday's Barclays Premier League Results
Arsenal 5-2 Tottenham
Man City 5-0 Aston Villa
West Brom 2-1 Chelsea
Reading 2-1 Everton
Liverpool 3-0 Wigan
Newcastle 1-2 Swansea
QPR 1-3 Southampton
Norwich 1-0 Man United