Serena Williams Favourite To Beat Venus But Form May Bring Sisters Closer

It is seven years since Venus Williams beat Serena Williams in a grand slam event, her victory here in the 2008 final also the last time she lifted a major title. On Monday the sisters will meet at Wimbledon once more, this time in the fourth round, and it is Serena who has everything to lose. (Serena and Venus Clash Highlights 'Manic Monday')

It would be a strange turn of events if the younger sister's hopes of completing her second "Serena slam" of four consecutive majors were to be ended by Venus. In 2002-03, when Serena won the French Open, Wimbledon, US Open and finally the Australian Open the following January to achieve the feat for the first time, it was Venus who was on the receiving end in all four finals. At 35, the odds are against the older sibling doing it but she will take heart from the fact that she won their last meeting, in Montreal last year , and the pressure, undoubtedly, is on the world No1. (Five Classic All-Williams Matches)

Four years ago Venus announced that she had been diagnosed with Sjogren's syndrome , an incurable auto-immune disease that leaves her short of energy and causes joint pain. Many medical experts thought she would struggle to play again, at least at the highest level, but the five-times Wimbledon champion has managed the illness incredibly well, climbing back up the rankings to be seeded 16 this year and playing some impressive tennis, reaching the fourth round without dropping a set. (Serena Tells Wimbledon Fans to Support Sister Venus)

In the interim, Serena has dominated the Tour, winning seven grand slams in the past three years, ever since she teamed up with Patrick Mouratoglou just before Wimbledon in 2012 . It is a partnership that has made her more consistent than ever, yielding 28 of her 67 titles, taking her grand slam tally to 20 and putting her halfway to the calendar year grand slam, something only three women have achieved.

But this will be the first time Mouratoglou has had to prepare Serena to face Venus in a grand slam and the Frenchman knows it's going to be a tough match, especially after the top seed came within two points of losing to Britain's Heather Watson in the previous round. "It's always special for Serena to play her sister," Mouratoglou said. "It's never easy to find the aggressivity and what she needs to do. I'll try to help her get that because in this special situation it's pretty difficult."

The stats are in Serena's favour: she leads 7-5 in grand slam meetings, 3-2 at Wimbledon and 14-11 overall, including five of the past six. But against Watson the American looked tense and almost paid the price. At the French Open last month, Williams managed to win five of her seven matches in three sets, often recovering from a set down to do so; here, Mouratoglou feels she's playing better, even if Watson almost pulled off a mighty shock.

"That was much closer than all the matches in Paris, where she was playing so bad, so she could only do better, suddenly she was clicking and then she was winning easily," he said. "She did a few things wrong [against Watson] but she didn't play badly. To a certain point, she didn't really need to know what to do, because she couldn't hit winners any more, she was forcing, she was trying to play closer to the lines and making too many unforced errors.

"But I think she's much better than in Paris. I think she's played better tennis, she started matches well, except the first round. She's there, I know. She lost her calmness [against Watson] but the match was really, really difficult for her, with the atmosphere and with Heather playing so well. In a way Heather took her out of her calmness and her game so she has all the credit. But she won, as she does, not always, but most of the time."

After scraping past Watson, Serena said Venus was the favourite for their match and her state of mind was evident when she said: "I'm not answering any more questions about the grand slam or the alleged Serena slam." Don't believe a word of it. She is intent on history.

In Serena's half of the draw, Maria Sharapova continues her title quest against Zarina Diyas of Kazakhstan but the defeat of the defending champion, Petra Kvitova , on Saturday means the bottom half of the draw is wide open, leaving opportunities for players such as Agnieszka Radwanska, the 2012 runner-up, who plays Kvitova's conqueror, Jelena Jankovic.