* Federer sweeps through
* Venus makes winning return
* Wozniacki, Sharapova, Henin win
Roger Federer fired up the Australian Open with a blistering start to his title defence on Monday, bringing some welcome warmth to an unseasonably cool Melbourne Park on opening day.
The first grand slam tournament of the year is famous for its searing heat but a blustery day with the occasional shower had the sweatshirt replacing the T-shirt as the garment of choice among much of the 15,000 crowd on the Rod Laver Arena.
Federer retained his trademark bandana even though the ease of his 6-1 6-1 6-3 victory over Slovakian Lukas Lacko and the cool afternoon air made the threat of sweat interfering with his vision slight.
"I thought I played great," the four-times Australian Open champion and second seed told reporters. "Tried to play offensive from the start and see where it takes me. It didn't work. I got back and played a bit more risky and so forth.
"I thought it was a good match. I don't think he played too bad himself. I saw some talent in him too and that's why I think I was really happy I chose that tactics early on to pressure him."
Federer taking risks meant a treat for the crowd, who witnessed some brilliant shot-making from the 16-times grand slam champion.
It was hard to believe that the Swiss maestro's backhand was once considered a weakness in his game as he stroked impossible looking winners off it from the back of the court to set up a second round meeting with Frenchman Gilles Simon.
Rafa Nadal's quest to become the first man since 1969 to hold all four grand slam titles simultaneously starts on Tuesday but this was an emphatic reminder that to do it, the Spaniard is likely to have to beat Federer at the top of his game.
Venus Williams, the women's fourth seed, made a winning return after four months out injured with a 6-3 6-2 win over Sara Errani of Italy.
"It's been so long," said the 30-year-old, who is hoping to add a first Australian Open crown to her seven grand slam titles.
"It definitely felt good today to go out there and play pretty clean tennis."
Venus is flying the family flag solo this year with her sister Serena, the 2010 champion, still unable to play after stepping on glass in a Munich restaurant last year.
Justine Henin, the losing finalist when Serena claimed her fifth title here last year, survived a tricky opening encounter against big-hitting Indian Sania Mirza to go through 5-7 6-3 6-1 despite 33 unforced errors.
Another two women hoping to contend, top seed Caroline Wozniacki and former champion Maria Sharapova, won the first two matches on centre court.
Dane Wozniacki claimed a hard-fought 6-3 6-4 win over Argentine Gisela Dulko, while Sharapova overcame a nervy start to beat Tamarine Tanasugarn 6-1 6-3 for her first Australian Open victory since she won her last major title here in 2008.
"Last year I played first match on centre (court) and, I lost. So I was kind of like, I don't want this to happen again this year," said Sharapova, who lost to fellow Russian Maria Kirilenko in the first round last year.
French Open champion Francesca Schiavone also showed plenty of grit as she came back from a set down to win her opening encounter against Spain's Arantxa Parra Santonja 6-7 6-2 6-4.
American 18th seed Sam Querrey was the first seeded player to fall and he took his time doing it, losing 5-7 6-2 3-6 6-1 8-6 to Pole Lukasz Kubot over three hours and 20 minutes.
Russian 23rd seed Nikolay Davydenko, three-times a quarter-finalist here, also made an early departure with a 6-3 4-6 7-6 6-4 defeat at the hands of German Florian Mayer.
Andy Roddick gave a forceful reminder that he once won a grand slam -- albeit at the U.S. Open in 2003 -- with a 6-1 6-2 6-2 rout of Czech Jan Hajek, firing down 18 aces but bemoaning the conditions.
"It was playing slow, so you had to kind of adjust," said the American eighth seed. "It wasn't hitting and jumping like it normally would here, and I think that's probably just the colder conditions."
Frenchman Gael Monfils said he took advantage of a flaw in his opponent's character to stage a remarkable comeback from two sets and a break down to beat Thiemo De Bakker 6-7 2-6 7-5 6-2 6-1.
"I know Thiemo a bit," he said. "Sometime he snaps in the head. We know he can snap. It's a weakness for him. So you play with that."