Mourinho facing questions after Knight's perfect day

Roman Abramovich headed for the Chelsea dressing room last night after a convincing 2-0 defeat to Aston Villa which leaves his side fourth in the Premier League and struggling for goals. The Russian billionaire and Chelsea owner certainly looked like a man in search of an explanation when he turned on his heel in the Villa Park directors' box and walked out a few minutes before the end of the match.

The Chelsea manager, Jose Mourinho, claimed later that the title race was wide open as Arsenal went ahead of his Chelsea side – although that is unlikely to be the news that his employer wants to hear. While Chelsea were eager to point out that Abramovich's dramatic exit from the stands did not preclude him leaving the ground altogether, there was enough in the performance to justify him walking out.

Mourinho's assessment that his side had "completely dominated" the home side was not shared by many at Villa Park where the home team won through Zat Knight's debut goal and a late second from Gabriel Agbonlahor.

It was the first time Chelsea have lost in the Premier League since January and Mourinho said that the late injury to Frank Lampard on Friday afternoon had forced him to change his plans after a week spent preparing his side for the game.

Mourinho said that Villa were one of many teams who had bought players during the summer and made the Premier League more open. "There's been a big improvement after the top four and it will be more normal for the big clubs to lose matches and points," he said. "The other teams have spent money and improved. It is more difficult to play against these teams and because of that the league is open."

Mourinho said: "Villa did well, they had the crowd behind them, they had spirit, they defended and tried to keep a clean sheet which they did.

"Chelsea played with complete domination of the game but we could not score a second goal. Their second goal means nothing to me. It's a goal that can happen when the game is broken."

Agbonlahor is unlikely to feel the same way about his goal for Villa and his part in an impressive attacking display with England new-boy Ashley Young on the opposite wing.

Mourinho was right when he said that Chelsea rarely concede goals at set-pieces, as they did with Knight in the 47th minute, but his argument that his side were "in complete control" in the first half stretched credulity.

"We lost Lampard on Friday after training and all the work we did that week we had to forget," Mourinho said. "It meant that we had to build a team on Saturday and try to play the game. But in football you pay for mistakes. We made our mistakes and you can't say that Villa didn't deserve it because they didn't make a defensive mistake."

Martin O'Neill, the Aston Villa manager, declared himself "delighted" with the performance and encouraged his players to believe that they could break the top four after they ascended to 10th in the Premier League. "This club should be built on those expectations," he said. "We are not as good as the top four sides but we are definitely a better side than last year.

"We have lots of talent in the team and we can play a bit. Ashley Young was sensational. You could hear the crowd's anticipation every time he got the ball at his feet."