Tuesday 8 September 2015 03:23, UK
Novak Djokovic admires the Williams sisters' rivalry, but finds it strange, insisting he could never compete against his own brother.
Serena and Venus Williams go head-to-head for the 27th time in the US Open quarter-finals on Tuesday as Serena bids to take one step closer to the calendar grand slam.
The world No 1 is just three wins away from becoming the first player to win all four major titles in the same year since Steffi Graf in 1988 and the fourth female to achieve the feat in history.
The possibility that Venus could spoil her younger sister's date with the history books, on home soil, would add a late twist to the siblings' story, which has included 28 major titles between them.
Djokovic would have been gunning for his own calendar slam in New York had it not been for a surprise defeat to Stan Wawrinka in the French Open final, but the Serb, who has two younger brothers, finds the Williams' rivalry difficult to understand.
"The first thing that comes to my mind is how would I feel to play my brother, and I don't think that would be possible, honestly," Djokovic said.
"I, in a way, admire what they're doing... for so many years to play against each other on such a big stage.
For me, somebody who has siblings, it's hard to watch, honestly, as well. It's just going after each other and after that going back to the same home like nothing happened.
"It's strange. They are sisters. They live together. They grew up together playing tennis.
"Of course they love each other, but they have to be very professional and go out on the court and play each other so many times in the finals of grand slams, in the biggest matches.
"They both were number ones in the world.
"Chapeau for that, but I don't know if I would be able to play my brother. It's not possible. I would not be able to handle it on the court."
The most famous sisters in tennis have met 13 times in grand slams since their first match at the Australian Open in 1998 and Serena has enjoyed the ascendancy in recent years, winning eight of the last 10.
Venus, however, has shown signs of a return to form at Flushing Meadows, with victories over rising star Belinda Bencic of Switzerland and Estonian Anett Kontaveit, who was dispatched in only 50 minutes - the shortest completed match of the tournament.
Serena and Venus have 115 singles titles between them, 43 doubles titles and they have shared eight major finals.
"I feel admiration," Djokovic said.
"But for me, somebody who has siblings, it's hard to watch, honestly, as well. It's just going after each other and after that going back to the same home like nothing happened. So that's a really tough one."
Djokovic added: "It's hard to talk about it. I think this rivalry between the two sisters, for me it just doesn't make sense.
"I can't see that as a rivalry between two siblings. Even though I respect them, the fact that they're able to switch off and be on the court regardless who is across the net.
"Of course they had big matches and both of them, they're great for the sport, no question about it. But I can't talk about their rivalry."
Watch Serena and Venus square-up in the quarter-finals of the US Open on Tuesday night live on Sky Sports 1. Not a Sky subscriber? Then watch through online streaming service NOW TV.
By purchasing a Sky Sports Day Pass for £6.99 or Sky Sports Week Pass for £10.99, you can enjoy access to all seven Sky Sports channels and watch on a TV with a NOW TV Box or on a range of devices.
