Liverpool suffered their second Anfield defeat in five days as Arsenal came from a goal down to claim all three points.
Manager Rafael Benitez had insisted the season started again today after the midweek Champions League defeat to Fiorentina.
But he did not get his wish even though Liverpool led at the break through Dirk Kuyt and should have had a penalty when William Gallas felled Steven Gerrard.
Arsenal grabbed two quick goals through a Glen Johnson own goal and an outstanding winner from Andrey Arshavin to heap more misery on the men from Merseyside.
Arshavin hit four last season in a 4-4 draw, but this time one was enough.
Bill Shankly's first official day behind the manager's desk at Liverpool was 50 years ago tomorrow, and Benitez will sit uncomfortably in that same office after this.
Liverpool made six changes from the side dumped out of the Champions League in midweek, with Fernando Torres back in the starting line-up for the first time since early November. Fabio Aurelio was brought in at left-back against the pace of Theo Walcott.
Arsenal were unrecognisable from the side that lost to Olympiacos in Greece, only Walcott being retained by manager Arsene Wenger.
With Manchester United, Chelsea, Manchester City and Spurs all dropping points 24 hours earlier, both sides were desperate to take advantage.
And at last Anfield was treated to a pulsating clash after weeks of insipid displays.
The tempo and passion came from both sides and Liverpool could have had two goals in the opening 13 minutes.
First Torres broke away, fed Gerrard to his right and then took the return before failing to lift the ball over Almunia when clear.
Two minutes later referee Howard Webb controversially denied Liverpool a penalty when Gallas felled Gerrard.
The Liverpool skipper may have pushed the ball too far, but Gallas clearly took Gerrard's legs.
Denilson was booked for a high tackle on Mascherano as Liverpool poured forward.
Arsenal survived, at times with difficulty, but still sought to play their intelligent, passing football out of defence.
Samir Nasri fired wide and Cesc Fabregas tested Jose Reina as the threat on the break from the Gunners became increasingly apparent.
But four minutes from the break Arsenal finally cracked.
Aurelio lifted a free-kick into the six-yard box, where Almunia, under intense pressure in the air, managed only a weak punch and Kuyt fired home from 10 yards.
Arsenal were furious with a supposed aerial assault on their goalkeeper, Wenger making the point angrily to fourth official Andre Marriner.
The Gunners' chief was even more upset two minutes later when it looked like Aurelio stopped Walcott's run with an arm across his face. Only a booking ensured.
Arsenal came out after the break fired up for the challenge and were level after 50 minutes.
Nasri tore down the right and fired in a low cross that Johnson turned past Reina for an own goal with Walcott lurking behind him.
Mascherano was soon booked for a foul on Fabregas and it was soon to get worse for Liverpool, and especially Johnson.
Fabregas' cross after 58 minutes eluded Johnson, who then failed to stop Arshavin turning to fire in off the post from 18 yards.
Benitez finally turned to Aquilani with 25 minutes left, Mascherano making way, and with the watching Xabi Alonso applauding from the directors' box as the man bought to replace him trotted on.
But Aquilani made little impact and finished the game limping.
As much as the first half had been so positive for an aggressive Liverpool, the second was becoming deeply frustrating.
Passes started going astray, Liverpool were no longer in Arsenal's faces, rather chasing their heels.
The passion had gone from Liverpool and the accomplished young Gunners had a measure of control they were not going to lose.
Arshavin was booked for one too many late challenges on defenders clearing the ball, then Fabregas for kicking the ball away from a free-kick.
David Ngog coming on for Yossi Benayoun and then Philipp Degen for a flagging, disconsolate Johnson did little to change the flow of the match and Liverpool now have just three wins in their last 15 games.