The Gunners made 10 changes from the side which had beaten Barcelona in midweek, but lacked a cutting edge in attack before they eventually made the breakthrough when Tomas Rosicky headed in at the start of the second half.

However, Orient produced a late rally and substitute Jonathan Tehoue drilled home with a minute left to earn a money-spinning replay which keeps alive the dream of a quarter-final at Manchester United.

With an already congested fixture list - which includes next Sunday's Carling Cup final against Birmingham at Wembley - the last thing Wenger will have wanted was a replay, which is set for March 2, just a week before they head out to Spain for the second leg of their Champions League last 16 clash.

"We have played the game with the right attitude and could not fault our fighting spirit, but you also have to give credit to Leyton Orient because they never gave up and fought very hard," Wenger said.

"As long as you do not score the second goal, that can happen.

"Overall it is a disappointment, but we are still in the competition and will now play at home.

"The most important thing is to go through.

"You had a match against a team which is technically superior, but fighting spirit has a chance."

Wenger, though, continued: "The most negative side of our result today is one more fixture and in fairness that is not what we needed.

"We have had problems in the cups against teams from the lower divisions to finish them off, but also we have given a lot.

"Sometimes, mentally, a breather would not be bad.

"What people forget is that since the beginning of December, we have played every three days, so sometimes to have a week where we could give the players a little breather would not be bad."

Yet Wenger did not begrudge Orient their big night at the Emirates.

He said: "It will make their budget for the season, if not more, and to scrap that off would be a blow to all the smaller clubs in England.

"They suffer already, so you would not have a lot of supporters to do that (scrap replays)."

Wenger admitted he had not heard of Tehoue, but is unlikely to forget the French striker now.

Orient boss Russell Slade hailed his very own "super sub", who has made a habit of netting crucial late strikes when introduced from the bench.

"To get that goal was great timing because Arsene Wenger could not get [Cesc] Fabregas or anyone else who could undo us on in the last 10 minutes," he said.

"When I have started with Jonathan, sometimes he has not made the impact he has coming off the bench.

"He has scored something like eight goals from 85 minutes onwards.

"In terms of super sub, forget about the [David] Faircloughs of this world - Tehoue, he is the boy, our secret weapon. Brilliant."

Slade continued: "Jonathan has had a really bad hamstring tear and missed a lot of pre-season, so that has also played his part in that he has not started that many.

"He is getting fitter and stronger, but while he keeps making an impact like that, I might just keep him on the bench.

"But he could turn out to be a very important player for us with 17 league games to go."

Flamboyant Orient chairman Barry Hearn had pledged to take the squad out to Las Vegas should they earn themselves a replay.

Slade quipped: "The lads had Elvis Presley on when the chairman walked into the changing room and were singing 'Viva Las Vegas'!

"The end of May or in June would be nice to get three or four days away, I am sure that would be fun."

The Orient boss - whose side are in the hunt to make the play-offs after losing just once in 14 league games - continued: "The quarter-final against United was a big carrot, but we have still to go back to the Emirates.

"We are humble, but proud that we have got this far and have another opportunity of playing against Arsenal in a fantastic stadium.

"I told the lads 'you will only enjoy it if you get some kind of performance' - and today we got that in the end."