MELBOURNE, Australia (AP) — Angelique Kerber remains the only Grand Slam singles winner in the Australian Open women's draw after surviving a frustrating fourth-round match.
For a while, though, it appeared Kerber's progression may have unraveled against No. 88 Hsieh Su-wei, a former top-ranked doubles player with a double-handed grip on both sides.
With a mix of slice and chips, lobs and bunts, whippy half-volleys and wristy crosscourt ground strokes off both wings, Hsieh pushed Kerber to the extremes and unsettled her rhythm.
Former No. 1-ranked Kerber finally got a succession of breaks to take the second set and dominate the third in a 4-6, 7-5, 6-1 victory on Monday afternoon.
"Credit to her. She played an unbelievable match," said Kerber, who won the Australian and U.S. Open titles and reached No. 1 in 2016. "I was feeling I was running everywhere. She was playing a lot of corners and drop shots. I was bringing a lot of balls back."
After holding it together to improve her 2018 winning streak to 13, Kerber faces U.S. Open quarterfinalist Madison Keys in the quarterfinals.
Keys returned to the quarterfinals here for the first time in three years with a 6-3, 6-2 win over No. 8-seeded Caroline Garcia. She has yet to drop a set at Melbourne Park and is averaging a brisk 62.5 minutes on court through her first four rounds.
Going into the fourth round, Keys had only dropped 14 games — the second fewest among the women through three rounds, just behind Kerber's 13 games.
Keys, the only American woman to reach the fourth round, said she feels like she's playing without pressure since returning from her wrist injury that forced her out of last year's Australian Open.
"I definitely realize how much l love it and how much pressure I put on myself," in the past, she said. "Just being really happy to be back out here and not at home in a cast."
Hsieh certainly made the most of her time back in the spotlight, returning to the fourth round at a major for the first round in a decade.
She took out one major winner — Wimbledon champion Garbine Muguruza — in the second round, and took a set off an almost dumbfounded Kerber to open the fourth.
Kerber, returning from a form slump that saw her ranking drop into the 20s in 2017, had to produce some of her best tennis.
She finished a 14-shot rally early in the second set by racing to the net and reaching at full stretch to track down a drop shot and send a forehand winner over the net post.
The 30-year-old German player had to serve to stay in the match in the ninth game of the second set. Then, after winning four straight points and converting a break-point chance with a sliding forehand winner down the line, Kerber crouched and screamed to celebrate the point.
She served out the set at love and then got critical service breaks in the first and fifth games of the final set as Hseih began to tire and started to miss the lines.
Hsieh has won two Grand Slam doubles titles, and was ranked No. 1 in doubles in 2014 but had a career-high singles ranking of 23. At age 32, she was oldest woman still in the singles draw. Recent work with former doubles champion — and Australian Open tournament director — Paul McNamee paid off with her singles ranking expected to rise again. She'll likely also attract more attention from sponsors after going through the singles in an unadorned white tank top and black skirt.
On the men's side, Tomas Berdych returned to the Australian Open quarterfinals for the seventh time after a 6-1, 6-4, 6-4 win over Fabio Fognini.
Berdych has been this far at Melbourne Park for seven of the last eight years. The only time he's failed to reach at least the quarters was last year when he lost in the third round to Roger Federer.
He could meet Federer again in the next round, if second-ranked Federer wins his fourth-round match against Marton Fucsovics later Monday.