Rafa Nadal and Kim Clijsters continued their smooth progress through the Australian Open as Melbourne Park finally witnessed a smattering of upsets and sustained periods of sunshine on Thursday.

The morning after Roger Federer survived a huge scare in his second round match, Nadal resumed normal service for the dominant top-two in the game with a 102-minute 6-2, 6-1 6-1 battering of world number 116 Ryan Sweeting.

The world number one eased to his 23rd successive victory at a major on Rod Laver Arena as he continued his pursuit of a fourth successive Grand Slam title, a feat only achieved by two men before him.

American Sweeting was game, but if the gap between Nadal and Federer and the rest of the top 10 is wide, there is a chasm separating the Spaniard from players outside the top 100.

Nadal married his usual muscular aggression with a fully functioning serve to set up a third-round meeting with local teenager Bernard Tomic, who shocked 31st-seeded Spaniard Feliciano Lopez 7-6, 7-6, 6-3.

Clijsters's 6-1, 6-3 victory over world number 62 Carla Suarez Navarro was so straightforward that the highlight came afterwards when the third seed handbagged the courtside interviewer over a text message he had sent to another player.

"You said you thought I was pregnant!" she told the former Grand Slam doubles champion Todd Woodbridge, continuing: "The text said: 'She looks really grumpy and her boobs look bigger'."

The three-times US Open champion denied she was expecting a second child, laughing as Woodbridge cringed in embarrassment and declared his television career over.

Jelena Jankovic had no cause for such levity after she became the first top-10 seed from either draw to exit the tournament, losing 7-6, 6-3 to China's Peng Shuai.

The seventh seed blew a 4-1 first-set lead and racked up 39 unforced errors as she slumped to her seventh defeat in her last eight matches.

"I mean, as a top player -- I've been number one in the world -- it's tough to sometimes accept those mistakes," a despairing Jankovic said.

"Really at times I couldn't believe I can do that, why am I doing that?"

Russians seeds Maria Kirilenko (18) and Alisa Kleybanova (24) as well as Spain's Maria Jose Martinez Sanchez (26) also headed for the exit after second round defeats.

Another upset came in the men's draw where big-serving Canadian qualifier Milos Raonic beat French 22nd seed Michael Llodra 7-6, 6-3, 7-6.

"This is my biggest result," the 20-year-old said.

"It's my biggest achievement to date. But I hope to do more than this. I feel that I can. I feel like I'm playing at a level... that I'm there with the top guys," he added.

Raonic will test his confidence against Russian Mikhail Youzhny in the third round after the 10th seed came through a gruelling five set match against Slovenian Blaz Kavcic 6-3, 6-1, 5-7, 4-6, 6-1.