A late mistake from Liverpool's Pepe Reina saw Arsenal to snatch a draw from a thrilling Premier League opener at Anfield this afternoon.
The Liverpool goalkeeper saw the ball rebound off him after Marouane Chamakh had hit the post in the final minute at Anfield to cancel out a David Ngog strike.
The goal was reward for a late spell of Arsenal pressure but it was unfortunate for Liverpool, who had survived most of the second half unscathed after the sending off of Joe Cole. The big-name summer signing from Chelsea was dismissed on his league debut for a reckless challenge on Arsenal debutant Laurent Koscielny.
Koscielny himself also received a red card, but not until moments before the final whistle when he earned a second booking for handball. The equaliser denied Liverpool what would have been only their fourth victory over the Gunners in their last 19 league meetings.
Fernando Torres was left in reserve, and later entered to a huge ovation after pledging his future to the club and recovering from a groin injury, but Arsenal missed two of their bigger stars more.
Cesc Fabregas and Robin van Persie were both said to be lacking match-fitness and while the former was absent altogether, the Dutchman made only a late appearance.
Thomas Vermaelen tested Reina early on with a fierce free-kick but aside from that, the first half was almost devoid of action until exploding into life in the closing moments.
Dirk Kuyt created Liverpool's first opportunity when he turned in the box but Manuel Almunia easily gathered his cross. New signing Milan Jovanovic cut through the Arsenal midfield with a determined run but Kuyt's final ball again found Almunia.
Arsenal's Samir Nasri had another long-range free-kick blocked and Vermaelen put the rebound wide. Gael Clichy had Arsenal's first serious chance from open play when he broke clear down the left after 30 minutes and fired a shot narrowly over from outside the box.
Liverpool thought an opportunity was opening up soon after when Almunia failed to claim a corner but referee Martin Atkinson spotted a foul by Daniel Agger on Vermaelen.
The action on the field was tight with neither side giving much away but Arsenal were almost caught when Jovanovic raced onto a long ball. With Cole walking back from an offside position, the Arsenal defence let the ball bounce and the Serbia international darted into the box, only to blast wide.
The game suddenly came alive in the closing minute of the opening period. First, Glen Johnson had a shot tipped over by Almunia and Ngog then had a header cleared off the line from the resulting corner.
The complexion of the game then changed completely in injury time as Cole was sent off for his lunge at Koscielny, who returned to the dressing room on a stretcher at the interval but ran out to start the second period as normal.
Liverpool seemed determined not to let their numerical disadvantage bother them and made a blistering start to the second half. They claimed the lead within two minutes of the restart as Mascherano threaded a ball into the box for Ngog and the Frenchman finished at the near post. It was his fourth goal of the season after three in Liverpool's first UEFA Europa League qualifying tie.
Not content with that, the Reds pushed forward again and Martin Skrtel headed wide from a dangerous Steven Gerrard free-kick. Ngog had an even better chance when he leapt to reach another Gerrard set-piece but could not direct his header on target. Kuyt created another fine chance after good work on the right but no-one could turn in his ball across goal.
Liverpool were reduced to nine men when Agger left the field for treatment after all three substitutes had been used. Arsenal stepped up the tempo and Tomas Rosicky showed great control with a slaloming run into the area before seeing his shot touched over by Reina. Maxi Rodriguez then cleared after a desperate goalmouth scramble.
The pressure eventually told in the last minute as Reina failed to grasp the ball after Chamakh hit the post from Rosicky's cross. Gerrard almost snatched victory as the game went into five minutes of injury time but Almunia kept out his free-kick. The game ended in controversy as Koscielny was dismissed.