Roland Garros semifinalist Jakub Mensik is done hiding in plain sight

And then came Jakub Mensik.

For months now, and especially in the past three weeks, most of the chatter in tennis has been about those hard-charging 20-and-under challengers in the new, post-Big Three era: Rafael Jodar, Joao Fonseca, Moise Kouame, Learner Tien, Martin Landaluce. When Mensik was included in the conversation, it was often as an afterthought.

Now, Mensik’s name is mostly spoken with awe. After treading water for the better part of a year following his surprising win last April at the Miami Open, the 20-year old from Czechia has gone off like fireworks, He shut down Fonseca—Brazil’s young prince—in Tuesday’s quarterfinals at Roland Garros, 6-4, 6-4, 7-6 (3). Forget the straight sets: the match was one for the ages when it comes to brilliant shotmaking.

Mensik will meet Alexander Zverev in Friday’s semifinals, in a mirror-image battle.  At 6-foot-6, Zverev has Mensik beat by just an inch. Both men serve rockets and carry failsafe backhands, their forehands apt to stray on a bad day at work. The signature quality that distinguishes both of them from the game’s other towers-of-power is their excellent movement.

John McEnroe, who has been calling matches on TNT, gives Mensik a slight edge in that department after watching the 20-year old run down Fonseca’s drop shots.

“Zverev is awesome moving side to side. But he’s not quite as good moving forward as Mensik,” McEnroe said. “If Mensik plays like that [again]  in the semifinals, he’s going to give Zverev a lot of trouble. The way he got up to those drop shops, and so skillful with that feel [when he gets there] ... I’ll tell you, he’s gonna be a handful for the next 10 years.”

Fonseca has never been loquacious or apt to disclose his deeper thoughts in his friendly confabs with the press. But on the heels of this loss he seemed a little shaken, his analysis clear-eyed and his words honest and true. Fonseca had played well and lost, and he knew it.

“His [Mensik’s]  return, both first and second serve, are pretty into the court and he puts a lot of pressure on the opponent,” Fonseca said. “He missed a very small amount [number] of returns and that put me in a tough position. Today was not about me playing bad, It was [all] to his merit ... He knows how to play in important moments. He's not afraid. He has courage.”

Mensik himself described the match as “insane,” and that description is close enough. How else to explain that Mensik failed to convert six match points late in the third set before he slammed the door on his gifted opponent's furious onslaught? Those match-point failures, with Fonseca serving at 5-6, included the kind that can make a player’s head explode: a probable blown call on a serve that went Foneseca’s way instead of ending the match, a blundering smash that made spectators and broadcasters gasp.

Others have come unglued over far less, but Mensik, stoic on the court, collegial and a little diffident in person, wiped the failures out of mind. The hold by Fonseca triggered the tiebreaker, but Mensik’s resolve was greater than Fonseca’s sense of relief at his great escape and the Czech prevailed.

He knows how to play in important moments. He's not afraid. He has courage. Joao Fonseca on Jakub Mensik

Everything about Mensik’s game, if not his placid personality, is outsized. There’s that explosive serve, and the rifle-shot, two-handed backhand. A smash that rattles the teeth. But those surprisingly nimble feet were essential to Mensik in his battle with Fonseca, a contest full of dazzling shotmaking and aggressive, go-for-broke swings that landed within the lines more than anyone—including either man—had a right to expect. Few expected Mensik to come out on top following Fonseca’s great wins over high seeds Novak Djokovic and Casper Ruud. but even fewer were surprised by the time he did.

Mensik, it turns out, has been hiding in plain sight. His name was on everyone’s tongue last April, after he pummeled his mentor Djokovic in the Miami final with an awesome display of firepower. The win catapulted Mensik to a ranking of No. 24. He sustained that level, then started this year with a title run in Auckland. An  abdominal muscle pull forced him to pull out of a much-anticipated fourth-round Australian Open showdown with Djokovic. Semi-fit in the ensuing weeks, Menik won only one match at each of the “sunshine double” tournaments.

By the tour moved to Europe and clay, peer rivals were busy stealing his thunder.  Mensik arrived in Paris toting an unimpressive 3-3 record over the clay season, and a ranking of No. 27—barely good enough to get him seeded. His clay season had been sabotaged, he said, by an infection in a toe just as he finished preparations for the Monte Carlo Masters, forcing him to pull out. Then he came down with a viral illness that knocked him back another two weeks.

“Before Madrid, I practiced just three, four days,” he explained. “I came to Madrid without any matches and I won two, but still I was not feeling good.”

Mensik continued to struggle, but by the start of Roland Garros he was finally healthy and hanging in with a seeding of No. 26  “I was basically super happy, finally playing pain-free. And yeah, as the tournament was going, I was playing better and better.”

Mensik was ready for anything on the red clay, and that’s just about what he got: an easy first-round win, then cramps and a trip off the court in a wheelchair in the debilitating heat following his second-round win over Mariano Navone. Solid wins over No. 8 seed Alex de Minaur and No. 11 Andrey Rublev were a prelude to his conquest of Fonseca.

Zverev will have the edge in experience when he meets Mensik on Friday, but somehow that detail doesn’t seem all that relevant in light of the Czech’s last win.