A bizarre own goal from Mathieu Flamini in the last minute gifted Swansea a 2-2 draw at the Emirates Stadium.
Wenger had called for a response to the "accident" of his side's 6-0 thrashing at Stamford Bridge which ruined his 1,000th match in charge.
Having trailed to an 11th minute header from Wilfried Bony, it was not until after the introduction of substitute Lukas Podolski just before the hour that Arsenal finally sparked into life midway through the second half.
Two goals in the space of 60 seconds from substitute Podolski and Olivier Giroud looked to have won the match for the Gunners.
However, Garry Monk's side - fighting against being dragged into the relegation battle - had defended resolutely and were themselves dangerous on the counter attack, eventually forcing a late equaliser when the ball broke to Leon Britton at the edge of the Arsenal penalty area.
As the midfielder pressed forwards, riding a couple of challenges, he stabbed a shot goalwards, which was partially blocked by Per Mertesacker, ricocheted off goalkeeper Wojciech Szczesny and back onto Flamini before rolling into the net.
Wenger was left less than impressed, and will be in no doubt of the challenges which now lie ahead in a campaign which has promised so much - and continues with the visit of Manchester City on Saturday.
Arsenal, though, also now face a fight to hold off Everton's charge for fourth spot, the Toffees having closed to within six points and a match in hand on the Gunners, whom they host next weekend.
"We want to go back to focus on the next game and this result hurts us a lot," said Wenger.
"The result is very disappointing, but the spirit we put in and the effort we put in was great and we have to take it on the chin.
"Sometimes when you lose big like we did at Chelsea, the next game most of the time you get a draw. The way it happened of course is more frustrating because we were 2-1 up with two minutes to go.
"I think at the moment it (title) is not the biggest worry we have. We have to be realistic a little bit and try to come back a bit in the next game."
Wenger added: "We have to look behind us and of course try to look in front of us.
"Everton won, so we have to focus and prepare well for the next game. It will be open until the end, but you can still have surprises as well.
"We have not too much room to come back into it, but we have to get some players back. It is difficult to fight with half the team out."
Wenger confirmed defender Laurent Koscielny would be out "for a while" with a calf problem, while midfield trio Aaron Ramsey, Jack Wilshere and Mesut Ozil are not yet ready to a return.
Swansea head coach Garry Monk was, meanwhile, perplexed by what he felt was an early final whistle from referee Lee Probert, blown up when Jonathan de Guzman looked to be breaking clear on goal.
"It was a poor decision. We scored and they have to restart the clock, so it would be five minutes minimum," Monk said.
"Then we are clean through on goal and 99 per cent a goalscoring opportunity is going to come, and they blow up 30 seconds short.
"I told the referee it was a very poor decision and it is very strange.
"When they put the clock up, it is minimum of that, and we are 30 seconds short, I just don't get it.
"I have never had it like that in any game I have ever played in."
Monk added: "I am happy because before the game if you had offered me a point I would have taken it, but with the way the match panned out, especially that last bit through on goal, I am probably frustrated we did not get to see the outcome of it.
"Unfortunately we got punished in a two-minute period, but we made sure we kept pushing and I knew we would get another chance.
"It was just about taking it whatever way it comes, and that (equaliser) was the least we deserved."