Steady Kerber advances to third round

By Larry Fine NEW YORK (Reuters) - Second seed Angelique Kerber stayed on track in her quest to unseat Serena Williams as world number one by beating Mirjana Lucic-Baroni of Croatia 6-2 7-6(7) on Wednesday to reach the third round of the U.S. Open. Australian Open winner Kerber rifled home an ace to finish the first set against the free swinging, 34-year-old Lucic-Baroni, then won a see-saw second set in which each player was broken three times on the way to a tiebreaker. The left-handed German