London - Arsene Wenger bemoaned the absence of Santi Cazorla after Arsenal were held to a drab goalless draw by struggling Middlesbrough.
Cazorla did not feature at the Emirates Stadium on Saturday and the Spanish midfielder was sorely missed by the spluttering Gunners.
Arsenal were frustrated by Middlesbrough as they wasted a chance to win for a seventh successive Premier League game and eighth in all competitions.
"You always miss Cazorla at home. From deep midfield into the final third his pass is always quick, accurate," said Wenger, whose side will be knocked out of first place if Manchester City avoid defeat against Southampton on Sunday.
"Cazorla, I don't really know when he will be back. We have to see how he recovers on Monday."
There was better news on France striker Olivier Giroud who is now set to return for Arsenal's home League Cup game with Reading on Tuesday.
"We didn't make enough from our set-pieces and crosses. So the first thing that comes to mind is whether a guy with more size and physical presence in the box could have helped," said Wenger.
"But we have just come out of six straight wins so I wouldn't like to jump on this kind of excuse.
"We have to deal with what we face and unfortunately we are used to scoring. We are an offensive team.
"We had five or six offensive players on the pitch at the end but we didn't manage to score so it's a bit frustrating.
"It's part of the Premier League. The other day Manchester City had a similar possession against Everton and didn't win.
"We have to find a way to be efficient even when the games are like that."
Wenger, whose side had beaten Ludogorets 6-0 in the Champions League on Wednesday, saw the Gunners run out of ideas and it was his own goalkeeper Petr Cech forced into a string of saves.
"It is a game where you had a lot of possession but there were tired legs and you are prone to counter-attacks," said the Frenchman, who was celebrating his 67th birthday on Saturday.
"You make it difficult for yourself. 75 per cent possession but you could have lost the game, that is modern football.
"When you are not sharp, you lack creativity in the final third. I must say, we gave everything but we did not have the legs today.
"The energy levels were a bit down but we were intelligent enough not to lose it. We were exposed at times. When you cannot win, you must not lose.
"They had chances but our goalkeeper saved us today. Petr Cech had a good performance in decisive phases.
"We tried. You don't win on command though. We lacked our creative potential around the box. That is part of it."
While Wenger was disappointed, Middlesbrough boss Aitor Karanka was delighted with the way his side played following a disappointing 1-0 loss to Watford last week.
"It was an amazing performance from my team," he said. "After the last defeat at home especially, it was tough for us.
"But we worked hard on the training field and today the plan worked really well. For me and for us it is great to come to the Emirates, and for the best Arsenal player to be Petr Cech.
"I think we should have won the game because we had good chances.
"We knew that we couldn't park the bus, but they have a lot of quality players. We were organised and our transition play was very good."