SHANGHAI, Oct 13 — World number 204 Valentin Vacherot said he was in shock yesterday after beating his cousin Arthur Rinderknech 4-6, 6-3, 6-3 to win the Shanghai Masters, becoming the lowest-ranked player to win an ATP 1000 tournament.

The unlikely all-family final between the 54th-ranked Frenchman Rinderknech and Vacherot, from Monaco, was described by the latter’s coach and half-brother Benjamin Balleret as a “fairytale”.

It was just the third ATP Masters 1000 final in history to feature two unseeded players.

“I don’t even understand why I’m sitting here right now,” the 26-year-old Vacherot said at the winner’s press conference.

“It’s crazy. I think I’m going to start realising in the next few days, but right now, I just want to enjoy the moment.”

Vacherot landed in Shanghai on a “little bit of a gamble”.

He was on the alternate list for the tournament — meaning he wasn’t even certain to take part — and found out just over a day before the qualifying rounds that he would play.

The performance that followed will propel the Monegasque from 204 to 40 in the rankings, according to the ATP website.

“The challenges were just everywhere,” he said, and his current situation was “surreal”.