Serena Williams marked her return to competition in Australia with a 6-2 6-3 win over Chanelle Scheepers in round one of the Brisbane International.
The 30-year-old former world number one last played down under when she won the Australian Open title in 2010.
It was her first match since she was fined for an outburst in September's US Open final defeat against Sam Stosur.
Former French Open champion Ana Ivanovic beat Tamira Paszek 6-3 6-3 and faces Kim Clijsters in round two.
Williams had her service broken in the opening game against South African Scheepers.
However, she fired seven aces and took advantage of eight double-faults by Scheepers to secure victory in 68 minutes and book a match with Serbian Bojana Jovanovski in the second round.
"That was definitely not easy, I think she (Scheepers) played really well," said Williams. "I didn't expect that."
Ivanovic, another former world number one, took a shade under 80 minutes to dispose of Austria's Paszek and she said: "There were some nerves involved, particularly early on but I felt I played well. Obviously there is still some room for improvement but it was the first match and I'm happy."
Four-time world number one Clijsters, now ranked 13th, has beaten Ivanovic in all four of their previous meetings.
The 28-year-old Belgian defeated Simona Halep of Romania in the opening round, her first match since August following an abdominal injury.
Ivanovic squandered five match points in her last match against Clijsters in March. Asked about their latest meeting, the Serbian added: "It will be a battle and I just want to try and apply things that I have worked on and see how that plays.
"I just need to go out there and test myself and push and see how far I am from the top players."
Top seed Stosur beat Anastasiya Yakimova of Belarus 6-2 6-3 later on Monday.
