Bacary Sagna says Arsenal paid the price for a poor first-half performance at Old Trafford on Sunday.
Arsène Wenger's side started tentatively against Manchester United and conceded a header from Robin van Persie before pushing the champions back after the break.
Sagna's deliveries from the right flank almost conjured up an equaliser but the France international was left to rue a slow start from the visitors.
If you lose decisive challenges you put yourself in trouble and that's what happened during the first half
"After playing like that during the first half, we couldn't expect more," Sagna told Arsenal Player. "The only positive today is we kept playing during the second half, we showed them we were a better team but we had to do this all through the game and we started playing too late.
"We wanted to finish [the week] on a good note, we didn't, so it's a bit hard to take. That is football, I think we learn about our team, about football as well.
"If we don't give the maximum and if you lose decisive challenges you put yourself in trouble and that's what happened during the first half.
"But I want to think positive, I want to keep looking forward, I want to think we are first and we want to stay first. The best way to do it is to respond well on the next game."
Sagna's crossing was one of the features of Arsenal's second-half improvement and the right back was happy with his contribution.
"Yes, I think we created some nice chances," he said. "Unfortunately we didn't score.
"We need to keep working hard, I need to keep working hard to try to serve the forward players as much as I can. I think I did quite well. Now we're going into the international week and we're going to be ready to start again from the Southampton game."Copyright 2014 The Arsenal Football Club plc. Permission to use quotations from this article is granted subject to appropriate credit being given to www.arsenal.com as the source 11 Nov 2013