Santi Cazorla converted an injury-time spotkick for the triumph.
Cech told arsenal.com: "It was a good free-kick. I got a touch and I was so pleased that I saw the ball going on the bar, but in the end it turned out to be an own goal.
"Which obviously, in that moment of the game, was against the run of play and we didn't need this unlucky moment. But I think our reaction was very good, we got a goal back in the first half, we tried to push for the winning goal. It came in the last minute but I think we were aggressive and we were searching for it so in the end we probably deserved a little bit of luck back."
He added: "I think we are not 100 per cent yet. Our game is not as fluent as it could be and it should be. But I think we are getting the results that we need and this is the most important sometimes when you are playing and you know not everything is happening the way you want, that you find a way to win games. Obviously we did so, so we are happy with the three points and we go game by game and try to improve every day."