Arsene Wenger admitted Arsenal had been lucky to get a 1-0 win at Burnley on Sunday after a last-ditch winner went in off Laurent Koscielny's arm.
Right at the end of injury time, a corner fell to Alex Oxlade-Chamberlain and his touch deflected in off Koscielny.
And manager Wenger told Sky Sports: "Honestly, from the bench I didn't even see the ball going in. Maybe we were a bit lucky there.
"Overall we lacked sharpness a little bit and our legs were a bit heavy today. That was a game today we could have won 1-0 and lost 1-0 as well on set pieces."
Koscielny said he was unsure how the ball had gone in, saying: "I tried to smash the ball with my right foot, and after I don't see where the ball is going.
"So I don't know if I touched the ball with my hand, but the ref gave us the goal and you need to respect the decision."
It was Arsenal's fifth straight Premier League win, rounding off a perfect week that began with a Premier League victory over Chelsea and continued with a Champions League win over Basel.
And it meant the Gunners pulled within two points of leaders Manchester City after their loss at Tottenham earlier Sunday.
"When you're five points behind teams of that quality, of course it's big," Wenger, who marked his 20th anniversary at the club on Saturday, said.
"So when you have the opportunity to get a bit closer, you have to not miss it.
"We knew it could be a big week for us. Maybe we played a bit with the handbrake, not with enough freedom, not enough combinations, not enough pace to get in behind.
"Is it we were below our level or because Burnley defended well? Certainly a bit of both."