Alexander Zverev ended Andrey Rublev's 15-match winning streak and moved into the quarterfinals with a 6-4, 6-4, 6-4 win over the Russian player at Melbourne Arena.
Rublev hadn't lost a match since October, having won four matches at the Davis Cup finals and winning titles in Doha and Adelaide to start this season.
It is the first Australian Open quarterfinal for Zverev, and his third at a Grand Slam event. The seventh-seeded Zverev will next play 2014 Australian champion Stan Wawrinka.
Wawrinka has advanced to the Australian Open quarterfinals with a five-set victory over fourth-seeded Daniil Medvedev.
The 2014 Australian Open champion dominated the fourth-set tiebreaker and then broke Medvedev in the opening game of the deciding set. He won 6-2, 2-6, 4-6, 7-6 (2), 6-2.
Medvedev's only other loss so far in 2020 was to Novak Djokovic in the ATP Cup. Wawrinka will play either Alexander Zverev or Andrey Rublev in the quarterfinals.
Medvedev was given an unsportsmanlike conduct warning in the final set when he became upset with the umpire when he wasn't allowed to challenge a call.
It was his 300th tour-level win on hard courts.
