Roger Federer will look to restart his grass season in Halle, Germany, following an opening-round defeat in Stuttgart.

"It’s important for me, especially after the Stuttgart week, to come here and make sure I win my first-round match," he said at his pre-event press conference in Halle.

Federer decided to skip the clay-court season and fell to Tommy Haas in three sets in his return at Stuttgart. He attributed some of his shakiness to his recent lack of match play.

"It could have been better in Stuttgart, but then again I had match point. It wasn't like it was 6-2, 6-2," he said. "A comeback is never simple."

Federer begins against Yen-Hsun Lu, and could face Mischa Zverev in the second round.

"I want to make the right decisions on the tennis court," he said. "I’ll have the right focus and mind-set, that point-by-point mentality. That was a little bit off in Stuttgart, understandably so. I have to learn from that week."

Federer is an eight-time champion in Halle.