What do you think is Vacherot's ceiling? Despite him being much older, do you think he can have a comparable career to Fonseca or Mensik?
No. He's interesting, because he's such a late breakout player, with no real path of development beforehand. He finished 2024 ranked #140 at 26 years old, #31 at the end of 2025. That's the type of rise you see from good players in their early 20s, and great players around 18-20. But to see that rise from age 26 to 27 is exceedingly rare.
There's been lots of random Masters winners in Open Era history, but I can't think of any that were his age (26, almost 27) when they won their first, and had spend their entire career on the Challenger circuit. Even "lesser randos" like Albert Portas and Andrei Pavel were established top 100 journeymen for a few years.
What makes Vacherot interesting and hard to project is not only his late rise, but the fact that he's pretty much held a high level of play for half a year now. He's #21 in the race rankings...meaning, he didn't just win Shanghai and then vanish (Those race ranking points don't include Shanghai).
I think the best-case scenario is that he's a top 20 guy for a few years, maybe sniffs the top 10. He's the type of player who could seize an opportunity and sneak into a Slam final, but I think it highly unlikely he wins one, at least as long as one of Sincaraz are there to meet him.
As far as comparing him to Fonzie and Mensik, the age difference is huge. There's just not that much room to grow for a 27-year old, compared to a 19-20 year old. Exceptions happen, but even the great outlier, Stan Wawrinka, was almost 28 when he won his first Slam and he didn't really get any better than he was when he won that first one. And really, Stan is a bit overrated in that while he was able to play at a Big Four beating level, it was only for a brief spell, and really only a handful of tournaments.
I suspect what we're seeing is peak Vacherot right now, which is surprisingly good and a bonafide top 20 type - sort of on the level of prime Robert Bautista Agut or Gilles Simon. But I don't think he'll get much, if any, better.