Arsene Wenger admitted his Arsenal side cannot afford to continue to let opponents off the hook after conceding a two-goal lead against second-bottom West Ham in a 2-2 draw here at Upton Park.
The Gunners were set to close the gap on second-placed English champions Manchester United to just one point after Robin van Persie and William Gallas fired the visitors into a first-half lead in this all-London clash.
But West Ham rallied to claim a draw thanks to second-half goals from Carlton Cole and Alessandro Diamanti and, having seen his side concede a late equaliser in the Champions League clash with AZ Alkmaar last week, the Frenchman admitted his side have work to do.
"We were in control but as long as you don't score the third goal the game is not won," said Arsenal manager Wenger.
"In fairness West ham did continue to fight until the last minute and we conceded two goals from two set pieces. Generous ones.
"We are an intelligent team and an intelligent team makes the maximum result with the game they produce.
That is what we did not do," he said after Sunday's setback, going on to cite a fault that has long been a feature of his team's play.
"We complicated our game a little bit and had five or six chances in the second-half and we missed the final ball as we wanted to be a bit too complicated and that is what we have to learn."
He added: "It is a major missed opportunity of course. You don't have the luxury to miss opportunities in our job. You need to get points when you deserve to get points and sometimes when you don't deserve to get the points.
"Today (Sunday) we never got them when we deserved them, and that means we have not made the maximum of what we should have done."
Wenger disputed the decisions that led to both West Ham goals, a free-kick and then a penalty conceded by Alex Song for a foul on Cole.
But he added: "We have to keep the positives as we played well and are a strong team. We want to learn to finish these games off which is basically the most important lesson of the day.
"When you have to play a final ball, we had crosses in the second-half, we missed the final ball as we played too late. We have to learn that.
"We missed the moment and timing off the crosses in the second-half. We had five opportunities and not one arrived."
Gianfranco Zola was left frustrated by the late sending off of Scott Parker but the West Ham manager believes this game will prove to be a turning point in his side's season.
The Hammers remain second bottom with just six points from nine games but the Italian said: "Last week (at Stoke) I saw something, a change and it's very important and today I have seen something more.
"It was very difficult to come back from that situation but we did it and I'm very pleased and proud of them.
"I am more focused on the point and to give a signal we are there and we are fighting. Today was difficult and we did it.
"That means we can do it all the time. With that spirit and with the qualities we have in the team I think we can do better things."
Parker collected a second yellow card after handling the ball under a challenge from Cesc Fabregas and will now face a one match ban.
Zola added: "Scotty went for a header with the boy but he was pushed and then he touched it with his hands. It's a pity because he was playing well and is an important player for us."