Reina ricket gifts Gunners point
England midfielder Joe Cole was sent off on his league debut for Liverpool for a clumsy challenge on Arsenal debutant Laurent Koscielny who was himself dismissed just before the end for a second yellow card.
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Liverpool went ahead just after half-time when striker David Ngog lashed the ball past Arsenal goalkeeper Manuel Almunia on his near post and they looked set to take three points in Roy Hodgson's first league match in charge.
But Arsenal, who had lots of possession but created few chances, equalised when Marouane Chamakh headed against the post and Reina spilled the rebound into his own net with just 15 seconds of normal time remaining.
Neither team matched the devastating form of champions Chelsea who began their title defence with a 6-0 win over promoted West Bromwich Albion on Saturday.
Tottenham Hotspur and Manchester City, also expected to challenge for a top-four place, drew 0-0 at White Hart Lane Lane and Manchester United open their campaign at Old Trafford against promoted Newcastle United on Monday.
Hodgson could not hide his frustration at conceding a late goal.
"It was a bit disappointing to lose two points so close to the end, but it was a remarkable performance having to play the whole of the second half with 10 men," he told Sky Sports.
"There was no intention from Joe Cole to foul the player, he threw himself in to try and block the ball.. but when players try to block the ball, the referee often sees it as a worse foul than it was."
Arsenal manager Arsene Wenger, who has signed a new contract committing himself to the club until 2014, was relieved to take a point.
"We had a lot of possession but Liverpool defended very well and we did not create many chances," he said. "We kept going and did not give up and in the end came back to 1-1 which is a very good result at Liverpool."
Cole was dismissed just before half-time for a high tackle on Koscielny near Arsenal's corner flag. It was the first sending off of his career and he will miss Liverpool's next three games.
Liverpool hit back just after half-time, however, when Ngog, who scored three goals against Rabotnicki in the third qualifying round of the Europa League, struck again.
Despite their numerical advantage, Arsenal did not seriously threaten until the 86th minute when Reina made a stunning save from substitute Tomas Rosicky, tipping his 15-metre drive over the bar.
But the Spaniard was at fault when a cross from Rosicky was headed against the post by Chamakh and although the rebound flew straight into Reina's hands he could only push the ball ba