Williams, 36, won this year's Australian Open while pregnant and gave birth to a baby girl in September. She has not played a competition since, raising questions over whether the 23-time Grand Slam winner would attempt to defend her title next month.
Former world number one Novak Djokovic said Radek Stepanek was joining his coaching team to complement Andre Agassi.
Maria Sharapova is under investigation in India after the collapse of a luxury housing project she had endorsed.
From 2019, Wimbledon and the Australian, French and US Opens will have only 16 seeded players in the men's and women's draws.
Five-time Grand Slam champion Maria Sharapova is under investigation by Indian police for cheating and criminal conspiracy after the collapse of a luxury housing project that she endorsed, a lawyer said on Tuesday.
Former Wimbledon champion Jana Novotna has died at the age of 49 after suffering from cancer, the WTA said on Monday.
Grigor Dimitrov will climb to third in the rankings behind only Rafael Nadal and Roger Federer as he begins to deliver decisively on his rich promise as a youngster.
David Goffin, who had never beaten his much-vaunted opponent, looked aggressive and did not allow Roger Federer to dictate play as the Swiss player lost his precision.
Serena Williams and husband Alexis Ohanian took to Instagram to share some intimate moments of their big day.
Roger Federer has never lost a single match to any of the remaining players in the ATP World Tour Finals 2017.
David Goffin had a shaky start, losing the first three games, but lost only two games after that in the entire match as he romped to victory in 71 minutes.
Serena Williams and Alexis Ohanian had announced their engagement in December after meeting in 2015 in Rome.
Jack Sock is the first American to reach the semi-finals of the ATP World Tour Finals event since Andy Roddick in 2007.
By extending his current winning streak to 13 matches, the 36-year-old advanced from the Tour Finals group stage with an unblemished 3-0 record for the 10th time in his glittering career.
The ex-minister from 2007-2010 alleged that Nadal had faked an injury in 2012, when he missed the final six months of the season due to knee problems, in order to hide a positive drug test.
Tennis superstar Serena Williams is used to hoisting trophies, but on Thursday, it looks like she'll be carrying a wedding bouquet.
Dimitrov has never quite lived up to his billing as the heir to Roger Federer's throne, but the world number six's eye-catching rout of Goffin was a reminder he is still young and gifted enough to finally make the breakthrough.
Dimitrov, who defeated Dominic Thiem in three sets in his Pete Sampras group opener, has already made history as the first Bulgarian to qualify for the season-ending Tour finals.