"In the first half it was hard work," he told arsenal.com. "We were running after the ball. It cost us a lot of energy.
"The second half was much easier. We had better organisation and a better shape. You could see that we created more chances, were more dangerous and in the end we could have won the game I think.
"It was really frustrating. We know we have the quality to beat Chelsea but it's all about results.
"We don't have to look too far ahead. There's still a long way to go. I'm still confident. You could see it [on Sunday] in the second half. I'm still confident we can get a good [position]."