There were several upsets on the first day of the Australian Open, though the biggest shocks came on the women's side, with local star Samantha Stosur and former world No.1 Caroline Wozniacki exiting in the opening round.
No such problems for the top seeds and defending champions Novak Djokovic and Serena Williams on Monday, even if allegations of widespread match-fixing cast a shadow over the opening day of the year's first grand slam.
Williams proved far too strong for Italian Camila Giorgi, dispelling any doubts about her fitness and form as the 34-year-old American moved freely on the troublesome knee that forced her to quit the Hopman Cup mid-match two weeks ago to win 6-4 7-5.
"It's great. It was an hour and 43 minutes and I didn't feel it at all," the six-times Australian Open champion said after her victory.
Djokovic, who also won three grand slams last year, has been far more active than Williams in recent months but has not been beaten since August, a run that never looked like ending in his 115-minute clash with South Korean teenager Chung Hyeon, which he won 6-3 6-2 6-4.
"A nice opening match with real Australian summer conditions," said Djokovic after embarking on his quest to match Roy Emerson's record of six Australian Open crowns.
Meanwhile a rampaging Roger Federer kicked off his 17th Melbourne campaign with a 6-2 6-1 6-2 demolition of Georgian battler Nikoloz Basilashvili.
No joy for Stosur, Wozniacki
Sam Stosur's Melbourne Park malaise remains as debilitating as ever, with the veteran local jolted from the Australian Open in straight sets by a Czech qualifier.
Stosur added another chapter to her miserable record at home on Monday night, losing 6-4 7-6 to Kristyna Pliskova.
Fourth-round finishes in 2006 and 2010 remain Stosur's best results in her home grand slam, and at age 31 that is unlikely to change for the 2011 US Open champion.
Caroline Wozniacki was unable to hide her disgust after the Dane's fall from grace continued with a deflating first-round exit.
Kazakhstan youngster Yulia Putintseva ended the two-time grand slam finalist's campaign in the first round for the second week, bumping Wozniacki out 1-6 7-6 6-4 to add to her early exit from Auckland the week before.
"I would say it's a pretty shi....y start to the season. It wasn't a pretty first set but I got it done and really should have closed it off in two," Wozniacki said after blowing a 6-1 4-2 advantage against the world No.76.
"I let her back into the match and it was basically my own fault that I'm not here as the winner."
The defeat leaves the Dane in danger of dropping out of the world's top 20 after the Open and the 25-year-old admits she's unsure how, when, where or if she'll get her season back on track.
"I don't know. I haven't really gotten that far yet," Wozniacki said. "But I guess just go back on the practice court and that's really all you can do."
Another shock came earlier when new Auckland champion Sloane Stephens was knocked out in straight sets by Chinese qualifier Wang Qiang, Wang prevailing 6-3 6-3 over the 24th-seeded American.
The new men's Auckland champion Roberto Bautista Agut struggled to put away Slovakian Martin Klizan, but the Spanish 24th seed eventually won through 6-2 6-3 4-6 2-6 6-2.
The 17th seed Sara Errani was another big casualty, Russia's Margarita Gasparyan getting the better of the Italian 1-6 7-5 6-1.
Fifth seeded Russian Maria Sharapova had no difficulties dispatching Japan's Nao Hibino 6-1 6-3.
Both Czech sixth seeds Petra Kvitova and Tomas Berdych had straight sets wins, Kvitova beat Thai qualifier Luksika Kumkhum 6-3 6-1 while Berdych had little trouble either with Indian Yuki Bhambri, winning 7-5 6-1 6-2.
Japanese seventh seed Kei Nishikori also progressed easily over Germany's Philipp Kohlschreiber.
Others to progress included 12th-seeded Croat Marin Cilic, who beat Dutchman Thiemo de Bakker 6-7 7-5 6-2 6-4.
Ninth seeded Frenchman Jo-Wilfried Tsonga needed four sets to beat former finalist Marcos Baghdatis of Cyprus 6-4 4-6 6-4 6-2.
Australian 29th seed Nick Kyrgios had a much easier passage to the second round with a 6-2 7-5 6-2 cruise past Spain's Pablo Carreno
American wildcard Noah Rubin put French 17th seed Benoit Paire out in three tiebreaks 7-6 7-6 7-6, while Argentina's Federico Delbonis was gifted his win over 22nd seed Ivo Karlovic, who retired in the third set while the big-serving Croat was two sets down.
Qualifier Renzo Olivo of Argentina knocked out 2014 Auckland champion Jiri Vesely of the Czech Republic in a five-setter, 7-6 2-6 1-6 6-4 6-4.
Also through without incident on the women's side were fourth seed Agnieszka Radwanska of Poland, 10th-seeded Spaniard Carla Suarez, 13th seed Roberta Vinci of Italy, 12th-seeded Swiss Belinda Bencic and the 23rd-seeded Russian Svetlana Kuznetsova - who won the Sydney International last weekend.
- AAP, Reuters