Arsenal manager Arsene Wenger says his side lost against Swansea City because of bad luck and poor decisions made by referee Robert Madley.
The Gunners lost a golden opportunity to move closer to leaders Leicester City as they suffered yet another Premier League defeat at home.
And the Frenchman opted to blame the referee at the end of the game as he confirmed goalkeeper Petr Cech pulled his hamstring in stoppage time.
"I believe we were really unlucky with our finishing and some decisions today," Wenger told BBC Sport.
"They had two shots on target and two goals.
"We stopped playing before the first goal because there was a foul on Mesut Ozil. There were hands around his neck and it should have been a free-kick for us.
"We need to bounce-back very quickly now.
"Petr Cech is injured. I think it will keep him out of the game against Tottenham at the weekend. But I have full-confidence in David Ospina."