MELBOURNE: An aggressive Serena Williams started her quest Monday for a record-equalling 24th Grand Slam title by thrashing Laura Siegemund on day one of the Australian Open.

The 39-year-old, playing an unparallelled 100th match at the tournament, looked sharp and smashed 16 winners in the 6-1, 6-1 romp in 56 minutes.

"This was a good start, it was vintage Serena," she said.

Williams, wearing a striking multi-coloured, one-legged catsuit, was broken in the opening game but hit back immediately and kept her foot on the pedal in a one-sided contest.

She showed no ill-effects of a shoulder injury that ruled her out of the semi-finals of the warm-up Yarra Valley Classic.

Williams has also been battling a lingering Achilles injury first sustained at last year's US Open, but has been in strong form so far in Melbourne.

The American, seeded 10th in her 20th Australian Open, needs one more major to equal Margaret Court's record Grand Slam tally.

She has not added to her glittering collection since beating her sister Venus in the Australian Open final in 2017 when she was pregnant with daughter Olympia.

Williams, the seven-time Australian Open champion, will play Serbia's Nina Stojanovic in the second round.