Alex de Minaur chalked up another priceless tennis lesson in cutting down the equal-tallest man in professional tennis to move into the Sydney International quarter-finals for a second straight year.
De Minaur was relieved after converting his one and only opportunity into the lone service break of the match in a hard-earned 6-4 7-6 (7-4) victory over towering American qualifier Reilly Opelka on Wednesday.
Opelka, who stands as high as tennis man mountain Ivo Karlovic at 211cm, thundered down 17 aces in 11 service games, but faltered from 4-1 in the second-set tiebreaker to prevail.
A sponge who claims every new experience as a learning one in what he hopes proves a journey to the top of men's tennis, de Minaur said he would again draw on the plucky win for future reference.
"I think I got lucky today. Reilly's an incredibly tough opponent," the teenager said.
"I have had a couple of matches against very high opponents with a big serve, and it's just very tough mentally.
"You've got to focus on your end of the court, got to focus on your serve and try to keep holding that and take advantage of the opportunities you have, which are not going to be a lot."
De Minaur, who has soared from No.208 to 29th in the world since making the Sydney final last year, has become a cult hero in front of home fans.
"There's nothing better than this. I love playing here. I love playing at home, loving playing in front of you guys and I can't wait to just keep it going," he said.
But the 19-year-old may have to share some of the crowd support on Thursday with fellow Sydneysider Jordan Thompson, who has made the most of his wildcard to reach the last eight for the first time in five attempts.
De Minaur took care of Thompson in straight sets last week in Brisbane, but is refusing to underestimate his long-time friend and rival.
"We both came from here, from Homebush, and he's always been like an older brother to me," he said.
"We have a great relationship, so it's going to be fun to go out there and play against him."
Another win over Thompson would leave de Minaur on track to reach successive Sydney finals after losing to Daniil Medvedev last year.
He could even play Stefanos Tsitsipas in a rematch of their 2018 Next Gen Final title decider after the Greek top seed eased into the last eight on Wednesday with a cruisy 6-3 6-4 win over Argentine lucky loser Guido Andreozzi.
Andreozzi's third-seeded compatriot Diego Schwartzman - the shortest man on the ATP Tour at 170cm - was more fortunate than him, advancing to the quarters with a 6-2 6-3 win over Spanish qualifier Guillermo Garcia-Lopez.