Wearing a bandage to cover up a nasty head wound, Martin Skrtel leapt high at a corner to score a powerful header in the seventh minute of stoppage time and rescue a 2-2 draw for 10-man Liverpool at Anfield.
Liverpool dominated the game but again lacked a cutting edge in the continued absence of injured striker Daniel Sturridge, with Philippe Coutinho's 45th-minute opener the only reward for its effervescent build-up play until Skrtel's late intervention.
Despite being overrun, Arsenal came from behind through goals by France internationals Mathieu Debuchy and Olivier Giroud from the team's first two efforts on target. The visitors should have gone on to take maximum points because Liverpool substitute Fabio Borini was sent off at the start of second-half stoppage time for two quick bookings.
"There's no doubt we deserved to win the game, our performance level was outstanding," Liverpool manager Brendan Rodgers said. "Our performance today was better than when we won here last (season) 5-1."
Last season's runner-up, Liverpool is in 10th place and nine points behind fourth-place West Ham heading toward the mid-point of the season.
A late goal was decisive in Sunday's other game, with Adam Johnson volleying home a 90th-minute winner for Sunderland in a 1-0 victory at northeast rival Newcastle. It sealed an unprecedented fourth straight derby win for Sunderland.
"It makes it a very special Christmas for us," said Sunderland manager Gus Poyet, whose team climbed four points clear of the relegation zone.
Arsenal's fragility in defence and central midfield continues to be a worry for manager Arsene Wenger, who has masterminded 17 straight seasons of Champions League football for the London club. Another top-four finish is expected, even though Arsenal is four points behind West Ham heading into the busy period of fixtures over the festive period.
"It's a point we are happy to take," Arsenal midfielder Mathieu Flamini said, "but we had the chance to win this game."
Coutinho's goal, a low shot that went in off the post from the edge of the box, was the least Liverpool deserved from a dominant first half but Arsenal managed to go into halftime level thanks to Debuchy's deflected header following a free kick.
The second half started with Skrtel needing lengthy treatment after being stamped on the head by Giroud — the reason where there was nine minutes of injury time, in which Skrtel scored the equalizer.
Giroud inflicted more pain on Liverpool by steering in Santi Cazorla's cross in the 64th but Arsenal could not hold on, even after Borini was dismissed for two yellow cards inside three minutes.
"We are disappointed to give a goal away with a free header from a corner," Wenger said.
Johnson finished off a length-of-the-field counterattack with a volley inside the near post, scoring at St. James' Park for the third season — each of them in wins for Sunderland.
"They must hate me here," he said.
Since ending Chelsea's unbeaten start to the season with a 2-1 win on Dec. 6, Newcastle has lost three straight games.