The bigger they are, the more likely Ash Barty is to make them fall.
Facing the very best in the business - and beating them - has now become the Australian's calling card.
She was at it again on Friday, looking perilously close to losing to the big-hitting world No.9 Karolina Pliskova in the Porsche Tennis Grand Prix quarter-final in Stuttgart before finding a gutsy way to eke out a win.
Increasingly, the woman who sits at the top of the rankings seems to have a bit of an aura about her when she's facing her rivals in the top 10.
Indeed, in her last eight matches against WTA top tenners, stretching back two years, Barty has come out on top in every one.
Having to defuse the bombs of Pliskova may have been the toughest of the lot as five times she came within two points of being knocked out before prevailing 2-6 6-1 7-5.
Ultimately, though, the Czech went the same way as Barty's other top-10 victims since 2019 - Petra Kvitova, Elina Svitolina, Aryna Sabalenka and Bianca Andreescu.
"I try and narrow that focus for every single match, regardless of who I am playing," said Barty, when asked about her remarkable record in the post-match press conference.
"But I think when you come up against top-10 opponents you have to go that level above to be able to play and it forces you to bring your best, to try and be able to compete every single time you are on the court.
"With a lot of the girls in the top 10, we've had plenty of matches going either way, different experiences.
"So each time I love that challenge of testing myself against the best."
Barty hasn't lost to a top-tenner since being beaten by Dutchwoman Kiki Bertens in the WTA Finals round robin match in Shenzhen in 2019 but the tests come thick and fast.
Next up in Saturday's semi-final will be Svitolina, the world No.5.
The Ukrainian, who saved two match points en route to knocking out holder Petra Kvitova, has a 5-2 win record against Barty but, perhaps significantly, has been beaten in the last two - in this year's Miami Open and the climax to the 2019 WTA Finals.
It promises to be a special occasion as Barty will be celebrating her 25th birthday - although her family were already able to celebrate the landmark after watching her victory over Pliskova in the early hours of Saturday morning back home in Australia.
"It was nice. My family were watching at home. So, they stayed up past midnight and were able to say happy birthday as soon as I got off the court," smiled Barty.
"It's exciting to be playing on my birthday. I mean it's what I love to do, playing against another tough opponent. There is no better challenge and no better way for me to celebrate."