Valentin Vacherot became Monaco's first ATP Tour singles champion and the lowest-ranked player in history to win a Masters 1000 event by beating his cousin Arthur Rinderknech in Shanghai.
The world number 204, who beat four-time Shanghai champion Novak Djokovic in the semi-finals, came from a set down for the sixth time in the tournament to win 4-6 6-3 6-3.
Rinderknech struck 12 winners and committed just two unforced errors on his way to winning the opening set, but from 3-3 in the second set Vacherot broke his opponent in consecutive games to lead by a break in the third.
A medical time out for Rinderkinech at 3-2 only delayed the inevitable as Vacherot, whose previous career earnings were £380,000, secured his maiden tour-level title and the winner’s cheque of £824,000.
"It is unreal what just happened. I have no idea what is happening right now. I am not even dreaming, it is just crazy," Vacherot said on the ATP Tour website.
"I am just so happy with my performances the past two weeks. I just want to thank everyone who has helped with my career since the beginning.
"There has to be one loser, but I think there are two winners today. One family that won and I think for the sport of tennis, the story is unreal.
"I feel when I am down, I have no choice and need to bring my A-game.
"In the first set I didn’t do that and he was playing better than me. I took my first chance to break in the second set and from that the crowd got more involved and we put on more of a show in the second part of the match."
Meanwhile, world number three Coco Gauff won the Wuhan Open without dropping a set after beating Jessica Pegula 6-4 7-5 in the final.
Two years after winning a doubles title in Miami with her fellow American, the 21-year-old showed no mercy in wrapping up victory in an hour and 42 minutes.
The French Open champion rallied from two breaks down in the second set before going on to win four straight games from 5-3 behind to close out victory.
"You're the three-set queen so I was determined not to let you get there today, because I felt like the odds would be in your favour in the third set," she told Pegula in her post-match interview.
"When I came on tour, you were one of the first people to be nice to me and welcome me with open arms and that really goes a long way and still goes a long way, so I appreciate you.
"It's great to finally play in a final against you and I hope for many more. It's an honour to share the court with you."
