Goals from Louis Saha and Emmanuel Adebayor put us in a commanding position after 33 minutes at the Emirates.
But it all changed when Bacary Sagna headed home for 2-1 after 40 minutes.
Robin Van Persie levelled two minutes later, the Gunners went ahead five minutes into the second half and by the midway point of the half, we were 5-2 down and out of it.
“It was a really strange game,” said the goalkeeper, who made outstanding saves from Tomas Rosicky and Yossi Benayoun when we were still in the hunt.
“We started dropping off and Arsenal, no matter what kind of form they are in, have some good footballers. We gave them way too much time and space.
“It was the snowball effect. We couldn’t stop it.
“We were trying to communicate things on the pitch but it was one of those games, a very uncharacteristic performance from us.
“We have to hope it’s a one-off, rip it up and move on to United.”