Coach Roberto Mancini says Internazionale should have scored a third goal against Udinese to avoid last-minute panic.
The hosts were reduced to nine men after Maurizio Domizzi and Emmanuel Agyemang-Badu both saw red but the Nerazzurri struggled in the dying stages of the game.
And the Italian was upset for the way his players failed to control the game in the second half.
"I don't know how close we are to make it to next season's Europa League but today's win is mighty important," Mancini said.
"But we have to play the way we did when it was 11 against 11. We failed to control the game [after Udinese were reduced to 9 men], we started to pass the ball around instead of trying to close the game.
"I am angry for all missed opportunities, we cannot afford to lose concentration. We have to use our brain, we were perfect when it was 11 against 11."