WhatsApp messages from family members are pouring in for Arthur Rinderknech and Valentin Vacherot. That’s because the two are cousins – they went head-to-head in the Shanghai Masters finals.

Both Rinderknech and Vacherot won their respective quarterfinal matchups, advancing to the semi-finals, where the former beat Daniil Medvedev and the latter knocked off Novak Djokovic.

“First of all, I followed my cousin,” Rinderknech said after defeating Felix Auger-Aliassime on Friday. “He was going through the emotions on Thursday, and I am trying to follow and battle and do the same as him. It has been incredible since the start of the tournament.”

A day earlier, Vacherot upset No. 10 Holger Rune, setting up Saturday’s duel against Djokovic. The Monaco native became the lowest-ranked player to play in an ATP 1000 semi-final since 1999.

“This is just unbelievable,” Vacherot said after the quarter-final win. “I didn’t come as a qualifier; I came as an alternate. I wasn’t even sure I was going to play qualifying.”

“The whole family is following from home,” Rinderknech said on Friday. “We are in our little world here.”

In the end, Vacherot beat his cousin 4-6, 6-3, 6-3.