Theo Walcott and Marouane Chamakh struck in the dying moments of extra time after Pavel Pogrebnyak appeared to have taken a night of high drama at Madejski Stadium into penalties. Arsenal had fought back to reach the quarter-finals for a 10th successive year after conceding a 4-0 lead in the first half and Wenger admitted it was an astonishing evening.
"We went from disaster to pride because we came back in the second half with a decent performance," he said. "At one point all we had was hope because it didn't look like we'd go through. But we got the disastrous first half out of our system."
He added: "The ninth goal looked like the winner because Reading had given a lot and mentally were down. But we looked comfortable in extra time.
"Reading had a fantastic first half and I know what it's like to be caught at 4-0 up. They should take credit from that performance.
"At 4-1 down I thought the comeback was possible because we were creating many chances in the second half. At 4-0 up a team thinks it has won the game. At 4-1 up you still think you've won.
"At 4-2 you suddenly realise it's not over and then the panic kicks in and that goes through the team.
"This competition was not one of our priorities but had we gone out in the way we could have, that would not have been one of my proudest moments. I was very proud of the way we responded in the second half."
Jason Roberts, a Laurent Koscielny own goal, Mikele Leigertwood and Noel Hunt helped Reading establish a 4-0 lead that looked unassailable given their dominance.
But Walcott, who finished with two goals, ignited Arsenal's fightback in first-half injury-time with the appearance of substitute Olivier Giroud adding extra urgency.
Source: PA
Source: PA