Serena Williams beat sister Venus in the 2009 final -- the last time they met at Wimbledon or in a grand slam.
For Serena it's a vital match in her quest for the grand slam while for Venus it's maybe her last chance to win Wimbledon.
But for both the Williams, Monday's sisterly showdown on Centre Court is a match neither is truly relishing.
Serena's coach Patrick Mouratoglou told CNN that the world number one would indeed rather she be facing another opponent.
"They're super close so this is not something she likes," the Frenchman revealed.
"Plus Venus is a super player. She's been No.1. She's won many grand slams and she's super dangerous on grass. But I guess if you want to win a grand slam you have to beat the best players and Venus is one of those. So she will have to beat her if she wants to win here."
