Daniil Medvedev eased past world No 7 Alex de Minaur 6-4, 6-4 on Friday to secure the last place in the Shanghai Masters semifinals and a date with unseeded Frenchman Arthur Rinderknech.
Rinderknech claimed the scalp of yet another seed in Canada's Felix Auger-Aliassime, 6-3, 6-4, to join his cousin Valentin Vacherot and four-time Shanghai champion Novak Djokovic in the last four.
Medvedev, a former world No 1 who has slipped down the rankings to 18th, said he was "super happy to beat such a tough player like Alex".
"It's been a tough year for me so to make the semis here is great," the Russian added.
Medvedev broke in the fifth game and then managed to hold despite a wobbly 10th in which he had to save a breakpoint and committed three double-faults.
De Minaur had his moments but the Australian looked somewhat flat, failing to capitalise when opportunities presented themselves.
A series of errors in the ninth game handed the second set to Medvedev, who finished with an ace and no further drama.
COUSINS IN LAST FOUR
Rinderknech, ranked 54 at the beginning of the tournament, has had a dream run in Shanghai, including beating world No 3 Alexander Zverev.
The 30-year-old's success has been matched by his cousin, Monaco's Vacherot, who booked his place in the last four on Thursday by eliminating Denmark's Holger Rune.
Rinderknech made easy work of 13th-ranked Auger-Aliassime, breaking in the sixth game with a down-the-line winner.
He started the second set with intention, breaking in the first game with a forehand to ensure the Canadian was never able to really get going.
"Sometimes you like to win ugly, and today I thought it was a pretty good-looking win," he joked.
Rinderknech said that getting through his own quarterfinal was far less stressful than watching Vacherot's the day before.
"I'm not used to watching someone and really wanting him to win so badly," he said.
"It was a lot easier for me to be on court today and just control my emotions and do my own thing, that I know how to do."
He said his family WhatsApp group was "burning" at the moment.
"Everybody is just living the little dream we are in, Val and I, so it's really enjoyable."