Australian Open 2018: Angelique Kerber battles past Hsieh Su-Wei; Tomas Berdych in 7th quarter-final at Melbourne
Kerber will play American Madison Keys in the quarterfinals while Berdych will play either defending champion Roger Federer or Marton Fucsovics.
Melbourne: Angelique Kerber extended her winning streak to 13 matches with a frustration-filled 4-6, 7-5, 6-2 victory over Hsieh Su-Wei as the 2016 champion advanced to the Australian Open quarter-finals.
Kerber overcame Hsieh's array of chip and drop shots off the Taiwanese player's unorthodox two-handed grip. At times, Kerber was frustrated with the shot selection by Hsieh, who had beaten Wimbledon champion Garbine Muguruza in the second round.
Hsieh saved two match points on her serve in the seventh game of the third set, forcing Kerber to serve out the match in the next game. She clinched the match with a forehand to the open court.
Kerber will play American Madison Keys in the quarterfinals.
Tomas Berdych booked his spot in the quarterfinals of the Australian Open 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.
The 19-seeded Czech veteran could play Federer again in the next round if Federer wins his fourth-round match against Marton Fucsovics later on Monday.
Berdych is 6-19 against Federer and hasn't beaten the Swiss star since 2013.
ATP rankings: Rafael Nadal stays at third spot despite Italian Open triumph; Novak Djokovic stays first
Nadal, a 13-time French Open winner, is also behind Daniil Medvedev, who suffered a second round exit in Rome to continue his struggles on clay.
Kenin, the Australian Open champion and French Open runner-up in 2020, wrote about the switch on Instagram on Friday.
The Italian teenager will face the 20-time Grand Slam winner for the second time, having impressed against Nadal in last year's French Open quarter-finals despite losing in straight sets.