An already depleted India suffered another blow on Saturday with Rohan Bopanna pulling out of the Davis Cup World Group Play-off tie against Spain, claiming that he suffered a knee injury during the US Open.
The Indian Davis Cup team is set for a battle of gigantic proportions as it takes on five-time champions Spain, who have packed the side with world class performers headlined by the legendary Rafael Nadal in their desperation to reclaim a spot in the elite World Group.
The 22-year-old Australian breezed past the 15-times Grand Slam champion in about one hour and 20 minutes.
Serena, a six-times champion in New York who is seeded 17th, will start her campaign against Polish world number 60 Magda Linette and could face Venus in the third round before a possible fourth-round showdown with Romanian top seed Halep.
Djokovic dropped only three games against Klizan.
Images from all the action on Day 4 of the Australian Open in Melbourne on Thursday
Nadal has turned back the clock to sweep through the European claycourt season with titles in Monte Carlo, Barcelona and Madrid and is a daunting obstacle for anyone with genuine title ambitions.
Roger Federer kept up his hopes of finishing the year as World No 1 when he downed Frenchman Jeremy Chardy 7-6(5), 6-7(5), 6-4 in the second round of the Paris Masters on Wednesday.
Bulgarian's Grigor Dimitrov claimed a first career win over former world number one Rafael Nadal at the eighth time of asking to reach the semi-finals of the China Open on Friday.
Kei Nishikori was crowned Barcelona Open champion for the second consecutive year after a hard-fought 6-4, 6-4 victory over surprise Spanish finalist Pablo Andujar on Sunday.
Defending champion Novak Djokovic defeated Belgium's Steve Darcis 6-0, 7-5 on Monday to power into the last 16 of the Miami Open.
Indian duo of Sania Mirza and Rohan Bopanna entered the quarterfinals of the mixed doubles event of tennis competition at the Rio Olympics with a straight-set win over Australian pair of Samantha Stosur and John Peers in Rio de Janeiro on Thursday. Sania and Bopanna, who are being touted as India's medal hope at the Olympics, won their opening round match 7-5 6-4 in 73 minutes.
Roger Federer rallied from a set down to beat Moldovan surprise package Radu Albot 4-6, 7-5, 6-3 in a stuttering start to the 20-times Grand Slam champion's Miami Open campaign on Saturday.
Andy Murray rallied from a set and a break down against Gilles Simon to advance to his first semi-final since he won last year's Wimbledon title while top seed David Ferrer retired with a thigh strain at the Acapulco International on Thursday.
Factbox on Rafael Nadal's French Open final wins
Stanislas Wawrinka did what he had to do with victory over a weary David Ferrer at the ATP World Tour Finals on Friday and now needs a favour from Rafael Nadal to reach the semi-finals.
Unseeded Russian Mikhail Youzhny denied top seed and defending champion David Ferrer a fourth Valencia Open title when he beat the world number three 6-3, 7-5 in the final of the Spaniard's home event on Sunday.
Tommy Haas kept alive his slim chances of qualifying for next month's ATP World Tour Finals when he edged past near namesake Robin Haase 6-3, 4-6, 6-4 to lift his 15th career title at the Vienna Open on Sunday.
Here is a factual guide on the man of the moment...
Osaka survives test to reach last 16
A summary of the matches from Day 9 at the French Open.
As India gear up to host five-time champions Spain in a Davis Cup World Group Play-off tie, Saketh Myneni knows the enormity of the task at hand.
Spanish tennis player Rafael Nadal, who will play this week in the Rio Open, downplayed public concerns over risks linked to the Zika virus in the Brazilian city that will host the Olympics in August, saying "people are living completely normal lives."
Novak Djokovic scraped over his first hurdle at the Rome Masters.
An emotional Lleyton Hewitt staved off retirement for at least one more match by beating countryman James Duckworth 7-6(5), 6-2, 6-4 to reach the second round of the Australian Open on Tuesday.
Andy Murray continued his strong clay court form by booking a place in the semi-finals of the Madrid Open with a 6-4, 7-5 victory over Milos Raonic.
Jack Sock started a new tradition on Thursday, one that the 23-year-old hopes will become a regular occurrence as he carves out a successful tennis career.
Defending champion Novak Djokovic survived a scare.
The Briton, who was thrashed 6-3 6-1 by the Croatian in the Dubai Championships in 2015, performed poorly in the first set and after recovering in the second he then surrendered his serve in the seventh game, giving Coric three break points.
'He probably deserves a player that is probably more dedicated to the game than I am. He deserves a better athlete than me'
IMAGES from matches played at the Miami Masters in Key Biscayne, Florida
Conchita Martinez will take over as Spain's Davis Cup captain for the Group I tie away to Russia.
Factbox on Spaniard Rafael Nadal, who beat Swiss Stanislas Wawrinka 6-2, 6-3, 6-1 to win his 10th French Open title on Sunday.
World number one Novak Djokovic survived a second set fightback from Slovak Martin Klizan before winning his opening match at the Miami Open 6-0, 5-7, 6-1.
'I had a tough season in the last few years, but I've had better preparation this year, even with a tough start to the season'
The pain of not living up to the favourites tag in the previous ties still rankles the Spanish Davis Cup team as Rafael Nadal said "special things" can happen for lower-ranked Indian players in the World Group play-off tie.
Rafael Nadal gave a much improved performance to advance into the quarter-finals of the Barcelona Open on Thursday, dispatching Spanish compatriot and crowd favourite David Ferrer 6-3, 6-3.
World No 1s Andy Murray and Angelique Kerber have been named top seeds for the first major of the season, Australian Open, which will commences on January 16.
World No 1 Novak Djokovic began his Paris Masters title defence with a routine 6-3, 6-4 win over German Philipp Kohlschreiber in the second round on Tuesday.
Toni Nadal has given a lukewarm response to the decision by the Spanish Tennis Federation (RFET) to appoint former women's Tour player Gala Leon as Spain's new Davis Cup captain.