(AFP) - German Angelique Kerber had just the match to settle her Grand Slam nerves on Monday, reaching the second round of the US Open with a crisp performance against ailing Polona Hercog.

Kerber, who toppled Serena Williams to lift the Australian Open crown in January and fell to the American in the Wimbledon final, was leading 6-0, 1-0 when 120th-ranked Hercog of Slovenia called it quits in the sultry heat of Flushing Meadows' Arthur Ashe stadium court.

"It's never the way I would like to finish the match, but I went out there to feel my rhythm and start the tournament well," Kerber said.

"I played the first set really good, so this is what I will take from this match, that I'm playing my tennis.

"For me, it's always tricky the first few rounds. So it's always good to have the first round done."

Kerber next faces Croatian Mirjana Lucic-Baroni, a 6-4, 6-1 winner over France's Alize Cornet.

Kerber's second seed in New York is her highest-ever for a Grand Slam, but the German said her current confidence in her game stems not from her seeding but from the solid form she has displayed all season to earn it.

"I'm not looking too much about the seeds because I know every round it's tough in the Grand Slam," she said.

"But I know that I'm playing good right now."

That's enough to go on with, Kerber added, refusing yet again to be drawn on her chances of supplanting Williams atop the world rankings at the conclusion of the championship.

"I will go out there to win every match going step by step," Kerber said.

"If the day will come someday it will be amazing. But let's just see."