Back on the court where he won his only Grand Slam title, Novak Djokovic overcame an early struggle against a journeyman Swiss player before advancing to the third round of the Australian Open.
The third-ranked Djokovic had nine double-faults and 52 unforced errors in his 3-6 6-1 6-1 6-3 win over Marco Chiudinelli, who was playing in his first Australian Open.
"I was well aware of his quality, and he played extremely well, especially in the first set and the start of the second," Djokovic said. "I was very lucky to get two sets to one up."
"This court is most special because I won my only Grand Slam here," the 22-year-old Serb said of Rod Laver Arena, where he beat Federer in the semi-finals en route to the 2008 title. "It has the nicest possible memories."
Djokovic will next play Uzbekistan's Denis Istomin, who beat Michael Berrer of Germany 7-5 6-3 6-4.
Sixth-seeded Nikolay Davydenko, who rarely gets onto the centre court at this stage of a Grand Slam, had a 6-3 6-3 6-0 win over Ukraine qualifier Illya Marchenko in the low-key manner which has typified an 11-match winning streak.
The 28-year-old Russian doesn't have the profile of Roger Federer or Rafael Nadal, and he's never made a Grand Slam final, but nobody has been playing much better lately.
He dominated Marchenko to extend a winning sequence that has included title runs at the World Tour Finals at the end of last year and Doha.
Davydenko's best run in Melbourne ended in a fourth-round loss in 2008, and if players progress according to their seedings, Davydenko would meet 15-time Grand Slam singles champion Federer in the quarter-finals at Melbourne Park.
Other men's results saw 2006 finalist Marcos Baghdatis struggle with cramp but he held on to beat Spain's David Ferrer 4-6 3-6 7-6 6-3 6-1.
Colombia's Alejandro Falla had a 6-4 6-1 6-3 win over Marcel Granollers and will play another Spaniard, Nicolas Almagro, who beat Benjamin Becker 6-4 6-2 3-6 4-6 6-3, in round three.
Former number one Ana Ivanovic crashed out in the second-round to Gisela Dulko of Argentina, 6-7 7-5 6-4.
Ivanovic, who lost the 2008 final in Melbourne, has slipped to 21st in the rankings and didn't win a tournament last year. It was her first loss to Dulko in their three meetings.
"It hurts. But it's a process," Ivanovic said of her hopes to regain a top-10 position. "I do feel better on the court. I'm playing much better. I feel like my old self. There are still some areas that are not there for me to rely on.
Venus Williams, in her 10th Australian Open, advanced to the third round 6-2 7-5 over Sybille Bammer of Austria. Williams has won seven Grand Slam singles titles, but has only been to the final once in Australia, when she lost to her sister, Serena, in 2003.
Serena Williams, who has won the season's first major every odd-numbered year since 2003, was on court this morning against Petra Kvitova of the Czech Republic.
Denmark's US Open finalist Caroline Wozniacki advanced 6-3 6-1 over Germany's Julia Goerges and will now play Israel's Shahar Peer, who beat Bulgaria's Tsvetana Pironkova 6-1 6-4.
Other winning women were No.7 Victoria Azarenka (Belarus), No.9 Vera Zvonareva (Russia), No.10 Agnieszka Radwanska (Poland), Li Na (China) and Spain's Carla Suarez Navarro.