Arsene Wenger admitted Andy Carroll exposed the weaknesses which have all but cost Arsenal the title this season after his hat-trick earned West Ham a 3-3 draw.
Laurent Koscielny (70) rescued a point for the Gunners, who had taken a 2-0 lead before Carroll's quickfire treble either side of the interval.
But Saturday's result means Wenger's men could find themselves 13 points adrift of leaders Leicester with just 18 to play for by Sunday evening.
The Arsenal boss reckoned Carroll was lucky to stay on the pitch after escaping a yellow card for a robust early challenge on Koscielny - but conceded his players could not cope with an aerial assault from the hosts.
"Why did we struggle with Carroll? Because he's good in the air," said Wenger.
"We had a good game but a bad result, and we paid for a weakness we have had all season - headers in our box.
"Yes of course, he was lucky to finish the game, but that doesn't mean we have to concede goals from headers; we have to look at ourselves."
Arsenal's title bid appears realistically over but Wenger vowed to keep fighting until the end of the season.
"We are third on 59 points and that's not where we want to be," he said.
"We have made it much more difficult to have a chance to win the championship but no matter, we have to keep going.
"You never know what will happen, and we have clubs chasing us as well, so we have to be serious and focus on finishing as high as possible."