American tennis great Serena Williams has fought back to beat the British player Heather Watson in an epic three-set match at Wimbledon, and reach the last 16.
Williams was trailing by three games to love in the deciding third set but came back to win 6-2 4-6 7-5 and stay on course for a 21st grand slam title.
Williams, who has already lifted this year's Australian and French Open titles, was forced to dig deep in front of a raucous home crowd after an error-strewn showing against the superb Watson, who is the doubles partner of New Zealand number one Marina Erakovic. They're into the second round at the London grass court major.
Williams, who said afterwards it was one of her toughest matches, will face her sister Venus in the last 16 - their 26th career meeting - as the 33-year-old continues her bid for a sixth Wimbledon title.
There were also wins for the men's top seed Novak Djokovic, the Serb beating Australia's Bernard Tomic in straight sets, while another Australian, the fiery Nick Kyrgios, upset seventh seeded Canadian Milos Raonic 5-7 7-5 7-6 6-3.
Fourth seed Stanislas Wawrinka also progressed to the fourth round, beating Spain's Fernando Verdasco.
Meanwhile, Marin Cilic and John Isner will attempt to finish their third round Wimbledon match on unday tied at 10-10 in the fifth set after play was suspended due to bad light.
A lengthy encounter always looked on the cards given their track records for going the distance and as the gloom descended on Court One play was suspended after four hours and 15 minutes.
American Isner, who beat Frenchman Nicolas Mahut 70-68 in the longest match in history, an 11 hour five minute epic in the first round of Wimbledon in 2010, lost the first set on a tiebreak before taking the second in similar fashion.
Croatian Cilic, who contested the second-longest men's singles match ever played at Wimbledon in 2012 with a five hour 31 minute victory over Sam Querrey, took the third 6-4 before towering Isner battled to win the fourth in another tiebreak.
Ninth seed Cilic squandered a match point in the 10th game of the fifth set and the pair will return on Saturday as they try to set up a fourth-round tie with American Denis Kudla.