Withdrawals and rain blight Australian Open

The Australian Open was left reeling on Monday after two of its biggest drawcards pulled out just hours before their matches.

Defending champion Andre Agassi and women's fifth seed Serena Williams left gaping holes in the tournament when they announced they had failed to beat injuries in time to play at the first grand slam of the year.

Agassi was sidelined by a wrist injury he picked up in a warm-up event at Kooyong.

Despite making a "210 percent" effort to play her first round match, Serena's chances were scuppered after she twisted her ankle at the Sydney International last week.

The tournament was also blighted by rain on Day One which prevented much play during the morning.

When the action did get underway, Russian fourth seed Yevgeny Kafelnikov and British sixth seed Tim Henman booked their second round spots.

Kafelnikov, champion here in 1999, beat Germany's Michael Kohlmann 6-3 6-3 6-2 while Henman made short work of Australian Todd Larkham 7-5 6-2 6-2.

French ninth seed Sandrine Testud exited, though, crashing 7-5 4-6 6-3 to compatriot Nathalie Dechy.

But the main action was off-court as the Open got underway.

Three-times champion Agassi delivered the first body blow to the tournament on Monday morning.

LONG-TERM CONCERN

"This is not good news for anyone," an ashen-faced Agassi told reporters at a hastily-arranged news conference.

"I saw a doctor on Sunday and when I woke up this morning my stomach was churning. I told (tournament director) Paul (McNamee) and it was a very difficult conversation.

"But hopefully this is something that, by treating it immediately, I can solve."

Agassi said the withdrawal was a bitter disappointment to the three-times champion, but the ramifications of the injury could prove worse.

"There's a long-term concern here...I am worried it is career-ending."

Wearing blue jeans instead of his tracksuit work clothes, the 31-year-old added: "At this age it doesn't take many weeks out of the sport for it to be career-ending."

Just a few hours later, Serena joined Agassi at the exit.

The 20-year-old had been due to play former Wimbledon champion Conchita Martinez on Day One of the tournament.

"If you only knew how big a disappointment it is to come all this way and then have to turn around go home and start all over.

"This is a really tough result for me. I think I could have done beyond well here.

"I was keeping hope alive as always in my case.

"As long as I am healthy this is just a small pebble that I will jump over."

SERENA DISAPPOINTED

Serena, younger sister of second seed Venus, said she was disappointed a request to play her match on Tuesday had not been granted by officials.

"It would be bogus of me...fabricating things if I said it didn't bother me but I'm not here to start a controversy. I will take this like a champion."

While Agassi returns to the U.S. straight away, Serena said she may stay in Melbourne to support her sister.

"I might stick around maybe, I love supporting Venus so you might see me in the stands. I will twiddle my thumbs."