AUCKLAND, New Zealand (AP) — Serena Williams ended four months on the sideline with flashes of form and occasional bouts of frustration in a 6-3, 6-4 win over Pauline Parmentier on Tuesday in the first round of the ASB Classic.

Williams, who rested various injuries after her semifinal exit at the U.S. Open, waited an extra day to make her first appearance of 2017 because rain on Monday forced the postponement of her match.

It was wind rather than rain that troubled the second-ranked Williams, with a swirling breeze on the open-air center court at the Auckland Tennis Center making it difficult to serve.

She only needed 74 minutes to beat No. 69-ranked Parmentier, serving eight aces — including one on match point — but also prolonged the match with a series of unforced errors, including four double-faults.

"You always feel rusty going out there for your first match," Williams said. "I definitely felt that rust, but mentally I knew how to get it back and get in there."

No. 19 Caroline Wozniacki also made a brief but impressive performance on center court Tuesday, beating American Nicole Gibbs 6-1, 6-0 in just 50 minutes.

Wozniacki looked sharp and confident, living up to her third seeding behind Serena and Venus Williams. Venus was scheduled to make her first appearance later Tuesday against New Zealand wild card Jade Lewis.

Serena had a shaky start, dropping serve in an opening game before Parmentier held her own serve at love. Williams found some form and confidence in the third game, which included a booming winner off a crosscourt forehand. She broke Parmentier's serve in the sixth and eighth games and held comfortably, serving out the set in 29 minutes.

There were signs of frustration from Williams as the wind picked up and she struggled to put her first serve in play. When she did, she won 80 percent of first serve points.

"It was so windy out there, but I guess in the wind you really have to be ready to move your feet," Williams said. "So I went to what my coach told me, and I was like 'you know how to play in the wind, you've done it many times before,' so I just tried to adjust to it."

She broke Parmentier in the third game of the second set, then immediately lost her own serve. Williams struggled to hold serve in the sixth game, saving three break points, then used two powerful winners to break again in the seventh game.

Williams, who won her Open-era, record-tying 22nd Grand Slam title at Wimbledon, said she's learned in recent months to better cope with the pressure of expectations in each match.

"It's something I feel like I'm dealing with better over the last few months, and I hope to be able to deal with it better this year," she said.