REUTERS: Alexander Zverev has not dropped a set on the way to Wednesday's Australian Open quarter-final but in three-times Grand Slam winner Stan Wawrinka the German knows he faces an opponent who will challenge him in every way possible.
Seventh seed Zverev, who won the 2018 season-ending ATP Finals, has not been beyond the quarter-finals of a Grand Slam but the 22-year-old has given himself another chance to do so with his 6-4 6-4 6-4 fourth-round win over Andrey Rublev.
"As I said in the beginning of the tournament, it's going to be a process. I hope every match will be better and better," he said of his improving form in Melbourne.
"The draw isn't getting easier."
Swiss Wawrinka, who is seeking a second title in Melbourne and his first Grand Slam since the 2016 U.S. Open, showed all his fighting qualities to beat Daniil Medvedev 6-2 2-6 4-6 7-6(2) 6-2 to reach the last eight.
Zverev has not lost to Wawrinka in two previous meetings but is not taking the 2014 Melbourne Park champion lightly.
"It's going to be difficult playing against him. He showed why he's a Slam champion, beating Medvedev, coming back from two-sets-to-one down, playing great tennis," Zverev said.
"He's still one of the toughest players ... especially here in Australia."
In other matches, Rafa Nadal continues his quest for a 20th Grand Slam crown when he takes on Austria's Dominic Thiem, an opponent who has beaten him four times on clay but has had no success on hardcourts.
"It is a match that's going to be tough, but (it) will be interesting, no? I'm excited to play against Dominic. I know I have to be at my best," Nadal said.
On the women's side, former world number one Garbine Muguruza, who has slipped to 32nd in the rankings, takes on Anastasia Pavlyuchenkova as she chases a third Grand Slam title.
Estonia's Anett Kontaveit, seeded 28th, opens proceedings at Rod Laver Arena against 2018 runner-up Simona Halep.
(Reporting by Shrivathsa Sridhar in Bengaluru; Editing by Peter Rutherford)