The Gunners were twice pulled back after taking the lead, but a late Theo Walcott goal saw them advance to the fifth round.

"Brighton is a good team and they made it very difficult for us. We made a little bit of a slow start, they were sharper than us in the first half," Wenger said.

"In the second half we were much more in the game and created chances. They play a game that is a very positive, technical game and they had a great spirit today.

"But overall in the end we have got that little bit of extra quality that got us through. It is a cup game, and you need to go through and that is what we did. We did our job but we needed to fight until the end.

Wenger admitted his decision to pick a slightly weakened starting 11 could have backfired but with the sheer number of games that are coming up, he felt rotation is the only way to manage the workload.

"Yes of course it is a gamble that you take, you know it can backfire, but I left a few out," he said.

"For example, (Santi) Cazorla not playing today, but it was for medical reasons, he couldn't play. Jack (Wilshere) too, a little bit to protect his ankle.

"But you cannot as well, with the number of games we play, play only with the same 11 in every single game. We play against Liverpool on Wednesday, we play Stoke on Saturday and then the players go away on international games.

"You have to rotate knowing that if it doesn't work you will of course be accused of making the wrong decision."