Serena Williams shook off the rust from a 15-month layoff due to pregnancy to win her opening match at the WTA Indian Wells event with a 7-5, 6-3 victory over Zarina Diyas.

The unseeded Williams was the top-ranked player in the world when she began her long layoff following her victory at the 2017 Australian Open, where she was already expecting daughter Alexis Olympia who was born in September.

Williams entered the court Thursday night to a loud ovation, with many in the half full stadium standing and applauding as she came out of the tunnel for just her third appearance in Indian Wells in the last 17 years.

After that it was a matter of gradually asserting herself by taking control of the rallies, and she got the first break of serve in the 11th game of the first set and secured the set in the next game on her third set point.

The 36-year-old American is the star attraction in Indian Wells, but behind her popularity this year was the mystery surrounding her match fitness and ball-striking ability.

The 23-time Grand Slam winner answered some of those questions Thursday by blasting four aces and winning 63 percent of her first-serve points against a tough opponent who claimed her first WTA title last year in Tokyo.