The Gunners' previously rock-solid defence was torn to shreds on Saturday, with Liverpool blasting four goals past them in a stunning opening 20 minutes before cruising to a 5-1 victory.
Arsenal surrendered their place at the top of the Premier League, slipping one point behind new front-runners Chelsea, and left many questioning whether they had the quality to last the distance in a tight battle for the championship.
Wenger's side have come in for flack for the manner of the defeat, but the Frenchman said it was simply an "accident" and to be treated as a one-off.
"It's always a disappointment to lose a game but I think it was an accident because we have been very stable defensively and we have to treat it like that," he told a news conference.
"We've just come back from a ten-game unbeaten run, you cannot consider one game as the trend, the pattern of our season.
"It's an accident, not welcome of course, a very disappointing one, but a successful season is decided how you respond to that.
"In any season you have disappointments. It's always down to the team to respond in a very positive way, that decides the success of the team."
Wenger was reportedly furious with his players during halftime at Anfield after two goals to Martin Skrtel and one each to Raheem Sterling and Daniel Sturridge effectively sealed the points with less than a quarter of the match completed.
He would not reveal what he said behind closed doors, but was confident they could rediscover the form that had seen them mount their first serious title challenge in recent seasons.
"We always tend to forget how good we are when we are not successful, and it's important that we remind (the team) that they've done up till now very well.
"We've worked very hard to be in this position. I love this group of players, they deserve success and I think they will respond in a very positive way tomorrow."
United are facing troubles of their own, with Sunday's 2-2 draw with bottom club Fulham leaving them stranded in seventh spot, 15 points off the pace and nine behind Liverpool in the fourth and final Champions League qualification spot.
Manager David Moyes is coming under increasing pressure as the poor results mount up, but Wenger, the Premier League's longest serving manager, offered his support for the beleaguered Scotsman.
"You need time and patience. You need to be in a strong club and I think he will be given time to do it," he said.
"When a person has been at a club for such a long time, there is always a void created when he goes. I believe that Moyes, if given time, will do that perfectly.
"They continue the same style of play," he added, referring to United under predecessor Alex Ferguson. "We consider them as a strong side and a team that has quality.
"Their season is difficult to judge. We consider we play against a good team and we want to beat them."
French striker Yaya Sanogo is available after three months out with a back injury, but long-term absentees Aaron Ramsey and Thomas Vermaelen remain sidelined.
Midfielder Mathieu Flamini is serving the final match of a three-match suspension.