Former Tottenham striker Robbie Keane dealt a fresh blow to Arsenal's fading title hopes as he secured a point for Barclays Premier League leaders Liverpool at the Emirates Stadium.
Arsenal had striker Emmanuel Adebayor sent off in the second half, which hampered their hopes of finding a winner after Keane's goal had cancelled out Robin van Persie's strike.
Arsene Wenger's men went into the match eight points off the pace, and perhaps more significantly they were - and remain - out of the top four following Aston Villa's win at West Ham.
Despite taking the lead through a fine strike from Van Persie after 24 minutes, it proved a false dawn as the Reds levelled before the break when Keane latched onto a long ball up-field and lashed in a thunderous shot.
Arsenal were forced to play the final 30 minutes with only 10 men after referee Howard Webb showed Adebayor his second yellow card for a clumsy challenge on Alvaro Arbeloa.
Liverpool were without manager Rafael Benitez, who was back on Merseyside recovering from an operation on his troublesome kidney stones.
His side could yet be knocked off top spot before Christmas by Chelsea, who play Everton tomorrow night - but for the Gunners, the new year looks set to be a hard battle to prove they have the stomach to somehow claw themselves back into contention.
Arsenal have beaten both United and Chelsea this season, but a failure to see off supposedly lesser sides has proved costly and resulted in them being overtaken by a resurgent Villa.
The leaders were, of course, set to present a stern test of Arsenal's credentials and there was a cagey opening to the game.
The first decent chance came in the ninth minute.
A long ball was knocked back by Keane from the edge of the Arsenal penalty area into the path of Reds captain Steven Gerrard, whose 20-yard effort was straight at Manuel Almunia.
Arsenal responded and a clipped ball in from Bacary Sagna on the right floated through to Adebayor, but his glanced, diving header just lacked the power to beat Jose Reina.
Arsenal then snatched the lead through Van Persie after 24 minutes.
Samir Nasri, fit again after an ankle problem, chipped a high ball through from just inside his own half towards the edge of the Liverpool penalty area.
The Dutchman collected it on his chest before turning two defenders and spinning to fire a right-footed shot into the net.
Liverpool, whose form has dipped in recent weeks, were clearly rattled after having looked quite comfortable.
However, slowly they found some composure and were level three minutes before the break.
The ball was pumped from deep inside the Liverpool half by Daniel Agger and bounced over centre-half Johan Djourou into the path of Keane.
The former Tottenham striker - barracked by sections of the home crowd - let the ball bounce again on into the Arsenal penalty area before blasting it past Almunia, wheeling away in delight at having silenced the jeers.
The Reds almost got another ahead of half-time, but Gerrard was just unable to convert Dirk Kuyt's low ball across goal when he arrived at the far post.
Almunia then produced a finger-tip save to deny the Dutchman and keep things level at the break.
Arsenal captain Cesc Fabregas had sustained what looked like a knee problem in a tackle with Spanish compatriot Xabi Alonso at the end of the first half, and was unable to continue, with Abou Diaby coming on.
Liverpool started strongly, as Almunia was forced to beat away a snap-shot from Lucas.
The tempo of the match increased as the hour approached, but it was the visitors who remained in the ascendancy as Agger headed wide following a corner.
Referee Webb then caused a storm when he reduced Arsenal to 10 men after Adebayor was shown a second yellow card for a hefty challenge on Arbeloa, who fell to the ground clutching his face.
Gunners boss Arsene Wenger was incensed, but replays suggested the Togo striker had indeed gone in with a raised boot, rather than a flaying arm, and as such probably merited a caution.
The atmosphere in the Emirates was highly charged, and Van Persie was another in the book when he fouled Agger.
To their credit the Gunners responded by pressing Diaby further forwards as they looked to get back in front.
Tempers, though, were never far from boiling point as Sagna became the third Arsenal man into the book when he tripped Albert Riera.
Nasri sent a 25-yard effort wide before a deep corner was whipped across the Liverpool goal from the right.
Almunia saved bravely at the feet of Kuyt as the visitors pressed for a winner.
Agger fired a 25-yard strike just over as both teams had to settle for a point.