Arsenal substitute Eddie Nketiah's equaliser in the final moments crushed Fulham's hopes of a big win and consigned them to a 1-1 draw, denying them a huge boost as they try to avoid relegation.
Nketiah scored in the seventh and final minute of added time on Sunday, tapping in a rebound at the near post.
Fulham's players and managers couldn't believe it since they only had to hang on for a few more seconds after going up 1-0 with a penalty in the 59th minute.
"We showed many times that we can play against the best and it is small things that means we don't win the game," Fulham defender Joachim Andersen said. "It is just hard now."
Fulham forward Josh Maja's emphatic spot kick had just before the hour sent Arsenal's Australia national team goalkeeper Mat Ryan the wrong way and went into the roof of the net.
It came after Mario Lemina had been fouled by Arsenal defender Gabriel.
A Fulham victory would have given manager Scott Parker's side a huge amount of belief going into the last five matches of the season.
His team are 18th place, with 27 points, as they try to fight out of the drop zone. Arsenal stayed in ninth place on 46 points.
"We would've liked three points but when I was called on I wanted to make an impact," Nketiah said. "I'm delighted to get a goal and salvage a point for the team."
Australian Associated Press