Elias and Mikael Ymer among the pairs of siblings currently playing professional tennis, along with Alexander Zverev and his brother Misha, and the Czech identical twin Plíšková sisters, Karolína and Kristýna.
The Ymers are currently the top two players in Sweden. Mikael is the higher ranked, at 83 in the world, while Elias is currently world number 163. However, the only senior tournament they have won is as a doubles pairing, when they lifted the doubles trophy at their home event of the Swedish Open in 2016.
Mikael did reach the final of the Winston Salem Open, a warm-up event for the US Open last August, but was then thrashed by the Russian Aslan Karatsev on that occasion.
However, Thursday proved to be red letter day for the pair. Playing in tournaments 7,000 km apart, they pulled off two of the biggest wins of their respective careers.
Elias got things going in Pune, India, where his world ranking meant that he had to come through two qualifying rounds just to enter the main draw.
He had battled past the Italian Gian Marco Moroni in the first round, but few gave him a chance against Karatsev of Russia, the top seed, the only man in the top 50 playing in the tournament.
Many commentators thought Karatsev just had to show up in Pune in order to assure his second trophy in 2022, but Elias had other ideas. He beat him in straight sets to set up a quarter-final meeting with another Italian, Stefano Travaglia.
Elias's feat had undoubtedly reached Mikael by the time that he stepped on court in Montpellier to face Gael Monfils, the local favourite and the number three seed. Not only did he beat the world number 16, but he thrashed him losing only three games in the process in a match that lasted less than an hour.
He will now play another Frenchman Richard Gasquet in the last eight.
The pair may not get any further in their respective tournaments, but will have plenty to talk about when they next get together.