Arsenal manager Arsene Wenger has backed his decision to not sign more defenders during the summer transfer window, claiming there were not enough quality players available in the market.

He spent around £80m to sign Alexis Sanchez, Mathieu Debuchy, David Ospina, Calum Chambers and Danny Welbeck.

However, Arsenal failed to secure both a defensive midfielder and a versatile defender to fill the gap left by Thomas Vermaelen's move to Barcelona.

With a number of defenders picking injuries during the start of the campaign, some people have questioned Wenger's transfer business but the manager refused to accept the blame.

"There is not a lot on the market and if you look at the other clubs, they had exactly the same problem. If you went anywhere, everybody is looking for defenders," Wenger said, according to Espn.

"I feel that we made a very good buy with Calum Chambers and we are a bit unlucky to lose Debuchy and Monreal at the same time together. No matter how many players you buy, you cannot have three players in every position because it is impossible to manage."

Wenger did confirm Per Mertesacker was fit to face Tottenham in the north London derby on Saturday 27 September, while Mathieu Flamini and Kieran Gibbs are also available.

"[Mertesacker] is available, he's in normal training today and I don't think there will be a problem." he said.

Meanwhile, Olivier Giroud, Theo Walcott, Mathieu Debuchy and Nacho Monreal will all miss the match.

And on the topic of the club profits and potential future signings, Wenger said: "Our profit is not as big as the years before because we spent a lot of money."

"It's good to have a little cushion in case we need to buy when the right players come up. If we need to strengthen the squad we will do it. In the last two years, we have invested a lot of money and we will continue to do so with the money that is available."