By Kamakshi Tandon

Persistent rain in Melbourne meant there were no matches played on the outside courts on Saturday, leaving some of the day’s best matches to be completed on Sunday. Fresh picks for Sunday include:

Mario Ancic (CRO)[9] vs. Andy Roddick (USA)[6] Rod Laver Arena – 2nd match

If Roddick can play with the variety and patience he did against Marat Safin in the third round, he should get through to the quarterfinals. The danger may be a letdown after the hype of that previous match, because the increasingly tough Ancic – the last player to defeat Roger Federer at Wimbledon – is fully capable of taking advantage.

Prediction: A lot of unreturnable serves.

Serena Williams (USA) vs. Jelena Jankovic (SRB)[11] Rod Laver Arena – 3rd match

After a gritty win over Nadia Petrova, Serena Williams has to turn around and show she’s capable of maintaining the level she showed at the end of that match. Jankovic is 12-1 this year and will come into the match drawing confidence from a 2-1 head-to-head lead over Williams. Conventional wisdom says Jankovic should win – but it also said that about Petrova.

Prediction: A lot of acrobatic gets.

Roger Federer (SUI)[1] vs. Novak Djokovic (SRB)[14] Rod Laver Arena – 4th match (1st night match)

There’s been a little edge between these two ever since Federer called out Djokovic on his frequent injury timeouts after their Davis Cup match last fall. Djokovic says he’s going into this match trying to win, but as Federer said, ominously, “Usually when I beat a guy twice, I know how to play him.”

Prediction: Djokovic called the trainer in his last match, but does it in against Federer at his peril.

Elena Dementieva (RUS)[7] vs. Nicole Vaidisova (CZE)[10] Vodafone Arena – 3rd match

Elena Dementieva’s form can often be gauged by her double faults, but evidence from her Australian Open matches so far is inconclusive: 6, 16, 4. Except for her serve, however, Dementieva is extremely solid while Vaidisova is still a streaky player. If the Czech is on a hot streak, she could knock out Dementieva in straight sets. But if it becomes a battle, the dogged Dementieva will likely prevail because Vaidisova tends to struggle mentally in such situations.

Prediction: Plenty of anguished looks after errors.