Serena Williams has said that she has an "amazing rivalry" with sister Venus Williams ahead of their meeting in the quarter-finals of the US Open.
The world number one has played her older sister 26 times before, winning 15 of their previous matches, including their last meeting at Wimbledon earlier this summer.
The defending champion at Flushing Meadows told reporters: "I think it's been an amazing rivalry. I think it's meant a lot. We've done a lot for the sport. Hopefully it can continue as long as we play.
"We really relish the opportunity. We're both happy to still be involved in getting so far. And it's still super intense. She's doing well and she wants to win this. So do I. It's not easy.
"She's beaten me so many times. I've taken a lot of losses off of her, more than anybody. She's a player that knows how to win, knows how to beat me, and knows my weaknesses better than anyone."
Venus has won just one of her last seven meetings with her sister.