The 26-year-old first reached the top last October but lost the spot 16 weeks later having not hoisted a Grand Slam trophy.
Sania Mirza and Rohan Bopanna, who are touted as India's best bet for a tennis medal in the 2016 Rio Summer Olympics, have been seeded fourth and will be up against the Australian duo of Samantha Stosur and John Peers in their opening mixed doubles match at the Games.
Serena Williams overpowered German Carina Witthoeft 6-2, 6-2 to set up a third-round clash with big sister Venus at the US Open on Wednesday.
Breeze though the outfits that caught the maximum shutterbugs at the final Grand Slam of the year.
Summary of sports events and persons who made news on Monday
Alexander Zverev got the better of older brother Mischa at the Citi Open in Washington on Thursday, winning their first meeting at an ATP Tour event 6-3, 7-5.
"I generally don't play with pain, but this is a Grand Slam and I just wanted to win," said the American.\n\n
Garbine Muguruza has to be the one taking charge in the Australian Open final against "fighter" Sofia Kenin if she is to win her third Grand Slam title, the Spaniard's coach Conchita Martinez said.
Big-serving Canadian Milos Raonic fired 19 aces to topple Sam Querrey 6-4, 6-4 and set up a second-round clash with either Dan Evans or Russian 10th seed Andrey Rublev.
In an exciting back-and-forth rubber lasting three hours 45 minutes, Siniakova held off the 19-year-old Fed Cup debutante to give the Czechs a 3-0 win in the final against a United States team who were the defending champions but were missing their top players.
Images from Day 3 of the Australian Open in Melbourne on Wednesday.
Defending champion Sloane Stephens was sent packing from the Miami Open on Sunday after a 6-3, 6-2 loss to Germany's Tatjana Maria in the third round.
Sania Mirza and Rohan Bopanna sqaundered a set advantage to lose to USA's Venus Williams and Rajiv Ram 6-2, 2-6, 3-10 in the Rio Olympics semi-finals on Saturday.
Venus Williams produced a vintage display full of guts and determination to grind out a 7-5, 6-7(3), 7-5 victory over Jelena Ostapenko at the WTA Finals on Tuesday to set up a White Group decider for a semi-finals berth against Garbine Muguruza.
Serena and Venus Williams rolled back the years as they swept through their last four clashes to set up a retro family final at the Australian Open on Thursday, their ninth meeting in a grand slam title-decider.
Sloane Stephens watched January's Australian Open from her couch, a large cast on her left foot rendering her immobile and raising questions in her mind about her ability to bounce back from the injury.
Former world number ones Venus Williams and Ana Ivanovic endured a humbling start to the season after the top two seeds were dumped out of the Auckland Classic in the first round by unheralded opponents.
Venus Williams crushed Frenchwoman Alize Cornet 6-3, 6-0 in the final of the Dubai Championship on Saturday, the veteran American bagging her first singles title since 2012.
Maria Sharapova withdrew from the Rogers Cup with a sore left arm on Thursday, putting the five-time grand slam champion's US Open participation in doubt.
IMAGES from the matches played at the Miami Masters on Sunday
South Korean Chung Hyeon managed to hang around against Roger Federer a little longer this time around, but only just, as the Swiss maestro advanced to the semi-finals of the BNP Paribas Open 7-5, 6-1 on Thursday.
Wimbledon women's champion Garbine Muguruza says she will savour her victory in order to prevent a similar slump in form to the one she suffered after winning the French Open in 2016.
The 15-year-old American phenom was forced to dig deep to become the youngest player since Anna Kournikova in 1996 to reach the third round
'I think what Venus and her sister have given our sport is absolutely tremendous. The way they've elevated women's tennis is truly inspiring'
As the first day's play got under way, she posted a video clip on Instagram of her pounding backhands on a clay court despite being absent from the tour since winning the Australian Open in January as she is expecting her first child.
A summary of the first day's play at the US Open.
Images from Day 3 of the French Open matches played at Roland Garros on Tuesday
Serena Williams will try to take a step closer to history on Saturday when she plays her third-round match at the US Open.
PHOTOS from day seven of the Wimbledon championships at the All England Lawn Tennis and Croquet Club in London on Monday
IMAGES from Day 2 of the US Open played at Flushing Meadows in New York on Tuesday.
She will now play Dutch 15th seed Kiki Bertens, who saw off Australian qualifier Daria Gavrilova 6-3, 6-3, in Saturday's semi-final on the red Foro Italico clay.
IMAGES from the matches played on Day 3 of the Wimbledon Lawn Tennis Championships at All England Lawn Tennis and Croquet Club on Wednesday
Check out the gold medallists from Day 9
'I knew I was the underdog and I was just enjoying it'
Vogue magazine, who were given exclusive rights to the photographs of the 'wedding of the year', put out some pictures from the Beauty and the Beast-themed wedding on their Instagram page.
In the video, which runs over nine minutes and was posted on Ines Ibbou's Instagram page, the world number 620 starts with "Dear Dominic" and goes on to talk about the difficulties she has had to endure and the sacrifices she needed to make in her career.
With next week's Australian Open in mind, a weary Venus Williams has opted to skip the Hobart International while her American compatriot Sloane Stephens has pulled out of the Sydney International with a minor wrist injury.
Serbia's Ana Ivanovic overcame a second set resistance to beat Belgium's Kirsten Flipkens on Friday and set up an Auckland Classic final against former World No 1 Venus Williams.
