Less than two minutes were on the clock when Eliaquim Mangala capitalised on an Eduardo error to fire past goalkeeper Vito Mannone and, two minutes later, Milan Jovanovic converted a penalty after William Gallas clipped the Serbia forward.
"We were caught cold by a team who were really ready and started out of the blocks at full power," said Wenger.
"Standard gave absolutely everything. They played like it was a cup final, with full commitment - and they deserve a lot of credit.
"When you go 2-0 down after five minutes, you know you have a big task in front of you. To win away from home in the Champions League and score three goals will always be tough.
"You are in a position where you have to attack with full power, without restriction, and know that the next goal will kill you.
The Gunners regained their composure and hit back on the stroke of half-time through Nicklas Bendtner, before Thomas Vermaelen tapped home and Eduardo converted a Cesc Fabregas corner from close range with his knee to complete the comeback.
"We could not afford to concede a third goal but had to try to come back to 2-1 at least before half-time - which is what we did," Wenger continued.
"In the second half, the game dropped a bit in physical intensity. When they got tired, we got some set-pieces and took advantage."
And the Frenchman admitted it was "inevitable" Eduardo would have a say in the match having been cleared to play after his two-match European suspension was rescinded this week.
The Croatia striker was initially banned by European football's governing body after being found guilty of diving to win a penalty in the Champions League qualifier against Celtic on 26 August.
"It is always inevitable with Eduardo," said Wenger. "He was caught out on the first goal but he is a guy who can always turn up on crosses because he has that anticipation."
As for the penalty his side conceded and the equaliser with which Arsenal scored - when Alex Song, from what appeared to be an offside position, seemed to handle the ball in the build-up - Wenger added: "The penalty looked harsh, but I have not seen it again.
"As for our equaliser, it was impossible to see from the bench."
Meanwhile, Liege coach Laszlo Boloni lamented the fact his side dropped so deep after taking the early lead.
"We started very well, but were not strong enough mentally to continue the same way in the second half," he said. "We sat back in midfield, so all the pressure was too much for us.
"Arsenal had good help from the referee at their second goal - two players were offside and there was also a handball.
"This was the moment when they got more motivation and we lost ours, but the biggest problem was we have to play better."
This page is best viewed in an up-to-date web browser with style sheets (CSS) enabled. While you will be able to view the content of this page in your current browser, you will not be able to get the full visual experience. Please consider upgrading your browser software or enabling style sheets (CSS) if you are able to do so.