Three-time defending champion Serena Williams begins her quest to complete a calendar-year Grand Slam while past winners Novak Djokovic and Rafael Nadal launch their campaigns Monday at the US Open.

World number one Williams has already captured the Australian and French Open and Wimbledon crowns this season and could be the first person since Steffi Graf in 1988 to capture all four major women's singles tennis crowns in the same year by hoisting the trophy at the end of the Flushing Meadows fortnight.

Russian third seed Maria Sharapova withdrew from the US Open on Sunday with a right leg injury, easing the path to a calendar-year Grand Slam for top-ranked Serena Williams.

US Open tournament director David Brewer announced Sharapova's exit, which allowed qualifying lucky loser Daria Kasatkina of Russia into the draw in Sharapova's place.

Ethiopian Mare Dibaba lived up to her billing as the world's fastest marathon runner by winning the grueling event at the world championships in a sprint finish on Sunday.

Dibaba timed 2hr 27min 35sec to edge Kenya's Helah Kiprop by just one second after a sprint in the final 50 meters of the race held in overcast, relatively cool conditions.

Usain Bolt has warned that people write him off at their peril after the imperious Jamaican sealed another world treble gold despite an injury-hit season.

Bolt anchored Jamaica to victory in the 4x100m relay to add to his wins in both the 100m and 200m, trumping his much-touted and controversial American rival Justin Gatlin.

West Ham manager Slaven Bilic hailed his team for writing a memorable chapter in the club's history books after they ended a 52-year wait to taste success at Anfield with a shock 3-0 victory over Liverpool.

Goals from Manuel Lanzini, Mark Noble and Diafra Sakho secured the east London club their first win at Liverpool since September 1963, a dismal run of futility which Bilic brought to an end in just his fourth league game in charge on Saturday.

Manuel Pellegrini insists it is far too early for Manchester City to get carried away despite opening up an eight-point lead over Chelsea in the Premier League title race.

Pellegrini's side have maximum points from four matches after beating Watford 2-0 at Eastlands on Saturday.

Jose Mourinho has no plans to spend big in the final few days of the transfer window in a bid to end champions Chelsea's early season Premier League malaise.

Chelsea's shock 2-1 loss at home to Crystal Palace on Saturday left Mourinho's men a significant eight points behind leaders Manchester City just four games into the current campaign.

Gareth Bale silenced his critics by scoring twice as Rafael Benitez got his first win as Real Madrid coach with a 5-0 thrashing of Real Betis.

Madrid remain two points behind Barcelona as Thomas Vermaelen was the unlikely hero for the European champions as they overcame stiff resistance from Malaga to win 1-0 at the Camp Nou.

Former world number one Rafael Nadal, struggling through what the Spaniard called his worst campaign in 11 years, said Saturday his form is very close to returning to top level.

Nadal has won titles this season at Hamburg, Stuttgart and Buenos Aires, but his record is 42-14 and he has slipped to the the eighth seed for the US Open, the final major championship of the year that begins Monday in New York.

Britain's Andy Murray has some sympathy for Australian bad boy Nick Kyrgios, the controversial 20-year-old he will face on Tuesday in the first round of the US Open.

Third seed Murray, who won the 2012 US Open and 2013 Wimbledon titles, said on Saturday that Kyrgios was wrong in his lurid verbal attack on Stan Wawrinka in Montreal earlier this month, but tennis officials, fans and players needed patience in dealing with him.