MELBOURNE, Australia — Eighth-seeded Kei Nishikori withstood 59 aces from Ivo Karlovic before beating the veteran Croatian, 6-3, 7-6 (6), 5-7, 5-7, 7-6 (10-7), and advancing to the third round at Melbourne Park.
Nishikori has not made it easy on himself so far this tournament. He lost the first two sets of his first-round match and then allowed Karlovic to get back into this match after taking a two-sets-to-none lead.
Nishikori, who dropped to his knees after hitting a service winner on match point, led 4-1 in the final-set 10-point tiebreaker but allowed Karlovic to take a 7-6 lead in it. But Karlovic hit a backhand long and then did the same with a service return, allowing Nishikori to take a lead he would not relinquish.
Karolina Pliskova, the No. 7 seed in the women’s draw, extended her winning start to the season by reaching the third round with a 4-6, 6-1, 6-0 victory over Madison Brengle.
Pliskova, a 2016 United States Open finalist, started this year with a run to the title at the Brisbane International, and she has a chance to regain the top ranking depending on her performance at this tournament.
After dropping serve twice in the first set against Brengle, Pliskova dominated the second and third sets and capped it with two aces.
“Some breaks, some good tennis and some bad mistakes from me, too,” Pliskova said. “The first set wasn’t very good from my side, but she played some good points and was very solid.”
Pliskova broke Brengle’s serve six times in seven chances after the opening set. She also finished with seven aces and had 14 service winners.
Pliskova has won all three of her matches against Brengle. Pliskova has advanced to the quarterfinals each of the last two years at Melbourne Park, including a loss to Simona Halep, an eventual finalist, last year.
She’ll next play No. 27 Camila Giorgi, who beat Iga Swiatek, 6-2, 6-0.
Madison Keys, the 2017 U.S. Open finalist, had a 6-3, 6-4 win over Anastasia Potapova to set up a third-round match against No. 12-seeded Elise Mertens, who beat Margarita Gasparyan, 6-1, 7-5.
In other early matches, the WTA Finals winner Elina Svitolina beat Viktoria Kuzmova, 6-4, 6-1, in 67 minutes; No. 13 Anastasija Sevastova beat the Canadian qualifier Bianca Andreescu, 6-3, 3-6, 6-2; and No. 21 Wang Qiang Wang had a 6-2, 6-3 win over Aleksandra Krunic.