Arsenal manager Arsene Wenger has admitted that his side "were not mentally prepared" for the visit of Watford to the Emirates Stadium this evening.

The Gunners' title hopes suffered a major setback as they slumped to their first ever Premier League defeat to the Hornets, failing to overturn two goals inside the opening 15 minutes from Younes Kaboul and Troy Deeney.

Wenger spent the match watching on from the stands as he served the second of his four-game touchline ban, and he admitted that he was unsure whether he could have had a greater impact from the dugout.

"I don't know, it's very difficult to know, it would be an excuse. We prepared for the game well. We were warned that Watford would come and make it very physical. Looking at the preparation, I have no basic regret on how we prepared for the game. Did we think subconsciously that we could just turn up and it will work? I don't know," he told reporters.

"But from the stands, I agree with you that our first-half was not at the level that we wanted. I don't think we have a physical power problem. We were not mentally prepared, we were not mentally ready to deal with these duels that we usually do. You don't make 47 points in the Premier League after 23 games if you have no physical power, but you have to switch it on at 100% in the Premier League, that's what it's all about.

"I am responsible for the results of the team so I am frustrated that we did not win. What the other teams do does not matter. What you want is to win the games and I am very frustrated not to win the game. We are at home and we have a great opportunity, of course it's frustrating and we have to learn from that, respond quickly and in a very convincing way."

The defeat leaves Arsenal third in the Premier League table, now nine points adrift of leaders Chelsea.