Arsene Wenger has admitted Arsenal failed to find the "creativity" to break down Tottenham Hotspur as the Gunners were held to a 1-1 draw in a contested North London derby on Sunday (6 November).
The French boss believes the final result was "fair" but played down suggestions Mauricio Pochettino surprised him after switching to a 3-5-2 formation.
Spurs dominated the first 30 minutes of the game as Pochettino went with a 3-5-2 formation with Kevin Wimmer, Eric Dier and Jan Vertonghen as the three central defenders. Arsenal managed to react in the last part of the first-half to take the lead after Kevin Wimmer's own goal, but Harry Kane's penalty levelled the game after the break, following Laurent Koscielny's foul on Moussa Dembélé.
"It was a game of high intensity where I felt in the first half we looked always like we could score every time we crossed the halfway line and in the second half we looked a bit more flat physically, a bit more less sharp and we couldn't find the creativity, the fluency around the box nor the vision we are used to," Wenger admitted after the game.
"I think our level dropped and we were a bit too stretched as well. Spurs defended well on some crosses in the final 10-15 minutes, I feel there were some balls where the fact that despite three tall players we couldn't make enough of corners and we missed some crosses as well. So overall, it was high intensity, technically I think our level dropped in the second half and the desire was there. Maybe the result is fair.
"I felt that when we were questioned in the final 30 minutes, we had no physical answer good enough to win the game. But we tried. I cannot question the spirit and the intensity of the game, but we lacked, we looked a bit flat."
The draw means Arsenal missed out on the chance to top the Premier League, staying fourth behind Liverpool, Chelsea and level with Manchester City while Tottenham remain in fifth place.
The Walcott admitted after the North London derby that Pochettino's decision to play three at the back "completely surprised" Arsenal. However, Wenger said that his side eventually had a plan to respond to that possibility.
"Not really, no (I was not surprised)," The Arsenal boss said. "We knew how to play against a back three, we knew that they could play with a back three. You know, I felt that that was not the basic problem. There were some other areas in the game where we had a problem."