Serena Williams reaches Dubai quarterfinals

DUBAI, United Arab Emirates, Feb. 18 (UPI) -- World No. 1 Serena Williams overcame an early deficit before claiming a second-round win Tuesday at the WTA's Dubai Duty Free Tennis Championships.

Williams dropped her serve twice in the first set, including the match's opening game, before taking a 7-6 (10-8), 6-0 decision over Ekaterina Makarova.

The first set took 77 minutes but the second was over in 29 as Williams took 70 percent -- 28-of-40 -- of the points in the second set. She had a 55-52 edge in points in the first set.

The Williams-Makarova pairing was the only second-round match on Tuesday's schedule but two seeded players fell in first-round matches.

Sixth-seeded Angelique Kerber dropped a tight 6-3, 3-6, 7-6 (8-6) decision to Ana Ivanovic. Both players had five breaks, with each getting one in the third set to force the deciding tiebreaker.

Alize Cornet advanced when, after Cornet went up 6-1, 1-1, No. 7-seeded Simona Halep retired with an Achilles tendon injury.

Halep defeated Kerber in Sunday's final of the WTA tournament in Qatar.

Fifth-seeded Jelena Jankovic stopped Maryna Zanevska 6-4, 6-3 and No. 8-seeded Carolina Wozniacki came away a 2-6, 6-3, 6-3 winner over Sabine Lisicki.

Also Tuesday, Kirsten Flipkens ousted Karolina Pliskova 6-1, 7-5 and Annika Beck beat Samantha Stosur 1-6, 6-1, 6-4.