The Gunners failed to capitalise on dropped points by London neighbours Chelsea against Fulham the day before.
Three points at the Emirates would have taken them into the Champions League places, but the visitors held out for a creditable point despite a second half onslaught from Arsene Wenger's side.
The Spanish midfielder claims Arsenal need to start taking their chances in front of goal if they want to finish in the top four this season - starting with QPR on New Year's Eve.
"I don't think you can ask much more than we put in to win the game." he told the club's official website. "Everyone tried really hard, it was one of those games. We had seven to 10 chances to win it but, as I said, it did not happen for us.
"Every side in the Premier League works hard but one goal is not enough. We have to be ruthless at home and keep more clean sheets to make sure we don't drop points.
"We have to stand up now," he went on. "This is a very important period and we have another game in four days. There is not much time to think at Christmas time. We did everything that we could to win the match. We have not done it so we have to improve for the next game against QPR."