Arsenal boss Arsene Wenger fears the psychological damage inflicted by Newcastle's fightback could have a lasting effect on his title-chasing side.
The Gunners lost ground in the Barclays Premier League title race after Newcastle staged an incredible comeback from 4-0 down to draw 4-4 at St James' Park on a day when 41 goals were scored in eight top-flight games.
The Gunners made the perfect start when Theo Walcott gave them a first-minute lead, and it was 2-0 inside three minutes when Johan Djourou headed home.
Robin van Persie made it three in the 10th minute and the Dutchman headed in his second and Arsenal's fourth 16 minutes later.
Abou Diaby was dismissed in the second half after reacting to a challenge by Joey Barton, who pulled one back for the Magpies from the penalty spot soon afterwards. Leon Best cut the gap to two goals in the 75th minute.
Barton scored a second from the spot before Cheik Tiote's long-range volley completed a stunning recovery by the Magpies.
Asked about the cost, Wenger said: "Mathematically, two points; psychologically, the damage is a bit bigger because everybody is, of course, very, very disappointed in the dressing room.
"But only the future will tell."
Sir Alex Ferguson admitted Manchester United blew a major opportunity after losing their 29-match unbeaten record at Wolves.
Victory against the Premier League's bottom side would have allowed United to open up a seven-point advantage over second-placed Arsenal.
But the visitors failed to capitalise on Nani's third-minute opener and eventually succumbed rather more meekly than anyone could have imagined.
"It was an opportunity," said Ferguson. "I said before the game, I do think Wolves are in a false position.
"But we had a great start. We made a lot of chances, particularly in the first half.
"Then in the second we were not at the races. Their keeper did not have many saves to make."
A Carlos Tevez hat-trick, which took his tally for the season to 18, gave third-placed Manchester City a 3-0 win at home to West Brom and moved them within a point of Arsenal.
Tevez tucked home a spot-kick after Steven Reid had fouled Aleksandar Kolarov and the Argentinian added a second after 20 minutes from a David Silva pass.
He completed his treble with a second penalty following a handball in the box by Jerome Thomas as the Baggies suffered a fifth successive league defeat away from home.
Coach David Platt said: "We have kept a clean sheet and that is a bonus. It is important for Joe Hart and his defenders. But what really counts is that we secured the three points."
Fifth-placed Tottenham joined Chelsea in fourth on 44 points with a last-gasp 2-1 win at home to Bolton.
Rafael van der Vaart tucked in a sixth-minute penalty for his 10th league goal of the season after Gary Cahill fouled Jermain Defoe, but the Dutchman missed a second spot-kick shortly afterwards.
It looked like a costly miss as Chelsea loanee Daniel Sturridge drew Bolton level, but Niko Kranjcar won it for Spurs in the 90th minute.
A second-half double from Robert Huth helped Stoke come from behind to claim a 3-2 win at home to Sunderland in the day's early kick-off at the Britannia Stadium.
Four goals from Louis Saha helped Everton to a 5-3 victory over Blackpool, who have now lost five Premier League games in a row.
Wigan secured only their third home league win of the season with a 4-3 victory over Lancashire neighbours Blackburn at the DW Stadium with James McCarthy's wonderful technical effort the highlight.
Fulham secured their 12th Premier League draw of the season as their game at Aston Villa finished 2-2.