It was the Russian's first competitive match since she withdrew from the St Petersburg Open in January.
Djokovic had his personal best winning sequence of 30 consecutive sets ended as Cilic played almost flawlessly aggressive tennis to draw first blood in a magnificent duel.
Roger Federer and Rafael Nadal powered to third-round wins at the BNP Paribas Open at Indian Wells on Tuesday to set up a mouth-watering rematch of their recent Australian Open final.
IMAGES from Australian Open matches played at Melbourne Park on Friday
A summary of sports events and persons who made news on Thursday
Somdev Devvarman would be India's while Yuki Bhambri is expected to carry his good from into the new season which is full of new challenges for the Indian players as ATP Aircel Chennai Open begins on Monday.
Top seed and defending champion Roger Federer returned to form to beat Japan's Kei Nishikori 6-4, 7-6(4) and reach the Shanghai Masters semi-finals on Friday.
The man who ended Britain's 77-year wait took only three more years to add to that glorious chapter. Andy Murray has now won the Wimbledon title twice in the last four years.
'You don't peak every week. One has to keep playing.' 'It's a sport where you have to play at least 25, 30 weeks a year.' 'You have to keep your head down and go with the flow.'
Images from Day 2 of the Australian Open in Melbourne on Tuesday
Images from Day 1 of the Australian Open in Melbourne on Monday.
A long year has taken its toll on some of the world's best tennis players but the relentless Novak Djokovic gives no indication that he is about to slacken the pace as he heads to the season-ending ATP World Tour finals in London.
IMAGES from Day 8 of the French Open, at Roland Garros, on Sunday.
The Big Four were always going to come into the year's first Grand Slam knowing fully well that their days of dominance are drawing to a close, if not already a thing of the past, says Dhruv Munjal.
Sania and her American partner Bethanie-Mattek Sands shocked second seeds Martina Hingis and Flavia Penneta, winning 6-3, 6-3 in the quarter-finals of Apia International. Rohan Bopanna and Daniel Nestor beat the Italian pair of Simone Bolelli and Fabio Fognini.
Summary of sports events and persons who made news on Thursday
Playing tennis professionally can be difficult physically, mentally and emotionally. But the tennis courts have often been the venue for for blossoming romance as love-struck couples decide it is game, set and match.
The 21-year-old German, one of the brightest stars in men's tennis, is yet to progress beyond the quarter-finals at a Grand Slam.
Ivan Lendl might be 'way too busy' to be his mentor but Tomas Berdych has not given up the dream of jumping on the 'super coach' bandwagon.
British number one Andy Murray hopes to marry Kim Sears next year after the former Wimbledon champion announced their engagement last week after nine years together.
Change might be afoot though, according to American great John McEnroe
Factbox on Serbia's Novak Djokovic who won his sixth Australian Open men's singles title on Sunday.
All the results from the matches played in the BNP Paribas Paris Masters on Tuesday
The charismatic 18-year-old Canadian has infatuated the New York crowds with his skill and on court panache that has made him the youngest man to make it into the fourth round of the US Open since American Michael Chang in 1989.
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.
Roger Federer was giving absolutely no guarantees about his form on Sunday, as the four-time finalist prepared for his first ATP start in more than two months at the Monte Carlo Masters. The 17-time Grand Slam winner will be starting afresh in the second round on the Monte Carlo Country Club clay after his early February knee operation. After hitting for nearly a week at the seaside venue overlooking the Mediterranean, the Swiss said that next week will be key for deciding his further schedule ahead of the French Open - the second major of the season. "I feel more rust than rest, but I am rested, mentally and physically," the 34-year-old said. "I don't think about the Roland Garros title," the 2009 Paris champion added.
World No 2 Rafael Nadal brushed aside American Jared Donaldson 6-1, 6-1 and will next face Diego Schwartzman after the Argentine beat Roberto Carballes 6-3, 6-1.
Novak Djokovic no longer sees winning Grand Slam titles or staying top of the men's ATP rankings as a priority in his tennis career, Serbia's world number one said on Friday.
Frenchman Benoit lost his temper in the third game of the second set when top seed Tsitsipas halted the match to attend to a broken shoe lace.
The first meeting between Nick Kyrgios and Stefanos Tsitsipas lived up to the hype on Saturday as the Australian saved a match point in a wildly entertaining 6-4, 3-6, 7-6(7) win to reach the Citi Open final.
Roger Federer showed flashes of his best but Novak Djokovic exposed the Swiss maestro's fading powers with a three-set victory at the ATP World Tour Finals on Tuesday.
Top seed Roger Federer suffered a shock 6-3, 6-4 defeat to Germany's Daniel Brands in his opening match at his home Swiss Open on Thursday - the latest setback for the former world number one.
Underarm serve could be an effective weapon in halting Rafael Nadal's annual rampage on clay most just chuckled.
'It ranks right at the top. Under the circumstances, playing against Nadal, such an important match, it's amazing," the 31-year-old told reporters after needing barely two hours to extend his perfect record in seven Australian Open finals'
Rafael Nadal withdrew from the Indian Wells tournament on Saturday with a knee injury, shortly before his eagerly-awaited semi-final clash with great rival Roger Federer.
Top seed Simona Halep came back from a set down for the third time in the tournament to beat Kazakhstan's rising star Elena Rybakina 3-6, 6-3, 7-6(5) to win the Dubai Duty Free Tennis Championships for the second time on Saturday. In a battle that lasted nearly two-and-a-half hours, the match came down to a tiebreak where two shots that went agonisingly wide for Rybakina eventually decided the title in front of a noisy crowd that constantly chanted Halep's name.
Rediff.com recaptures these and other exciting sporting moments from the week gone by....
Top seed Novak Djokovic launched his Shanghai Open title defence in fine style, breezing past Spain's Marcel Granollers 6-2, 6-0 on Wednesday. Later Roger Federer, playing his first singles match since a fourth-round exit at the US Open, made a brisk return to winning ways, beating Andreas Seppi 6-4, 6-3.
Ukrainian second seed Elina Svitolina ended Naomi Osaka's remarkable recent run with a 6-4, 6-2 triumph over the Indian Wells champion in the second round of the Miami Open on Friday.
A lot has happened to Andy Murray in the three years since he choked back the tears on Centre Court after a four-set defeat that handed Roger Federer the Wimbledon trophy for a seventh time.