Venus and Serena Williams won their Wimbledon doubles opener vs. No. 11 Andreja Klepac and Katarina Srebotnik on Thursday, 7-5, 6-3. The sisters, who have won five Wimbledon doubles titles together, exchanged sweet messages on Instagram after the victory.

Venus wrote, “5 sets today. 2 of them with my favorite tennis player.”

Serena replied, “No you are MY FAVORITE player. I love u so much ❤️❤️😍”

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5 sets today. 2 of them with my favorite tennis player @serenawilliams #sucess #wimbeldon

A post shared by Venus Williams (@venuswilliams) on Jun 30, 2016 at 1:38pm PDT

View this post on Instagram

No you are MY FAVORITE player. I love u so much ❤️❤️😍 #Repost @venuswilliams with @repostapp ・・・ 5 sets today. 2 of them with my favorite tennis player @serenawilliams #sucess #wimbeldon

A post shared by Serena Williams (@serenawilliams) on Jun 30, 2016 at 1:53pm PDT

True sisterly love. The Williams sisters will also play doubles in the Rio Olympics.