Osaka off the mark at Indian Wells with first round win over Errani
The four-time Grand Slam champion from Japan, fighting to lift a post-motherhood ranking of 287, sealed victory with a forehand winner.
Osaka then joked about heading back to her hotel to change nappies on her infant daughter, born last summer.
Thursday's victory featured five breaks of serve in the first set before the 2018 Indian Wells champion stepped it up for a straight-sets victory in 70 minutes.
"It's a pleasure to be back playing - but once I get home, I'm a mom," she said. "When I was pregnant I really wanted to return to playing.
"I know I'll have to play well to improve... but I'm excited to start winning more matches."
After losing in the Australian Open first round, the California-based player reached the Doha quarter-finals last month.
She next faces Liudmila Samsonova for a third-round spot.
Former WTA number one Caroline Wozniacki took a further step in her return to tennis, with the Dane finishing off a match interrupted the night before by rain.
It took only a few extra minutes on court for the number 204 to conclude victory against Zhu Lin of China 7-6 (8/6), 6-1 with Wozniacki now facing Croat Donna Vekic.
Venus Williams remained winless since August as the veteran lost a promising early lead and crashed out 2-6, 6-3, 6-0 to Nao Hibino of Japan.
The 43-year-old Williams last competed at the US Open in August and earned her last victory two weeks before in Cincinnati.
Britain's 250th-ranked Emma Raducanu scored a first-round win over number 96 qualifier Rebeka Masarova of Spain 6-2, 6-3, with the 2021 US Open champion next playing Ukrainian Dayana Yastremska.
"I was really pleased with how I stayed focused, didn't get down and competed really hard in tough situations," said Raducanu, who overcame eight double-faults.
In the men's draw, Australian Aleksandar Vukic lined up as the opening opponent for top seed Novak Djokovic after defeating Japan's Shintaro Mochizuki 7-6 (7/4), 7-6 (8/6).
Rising Czech Tomas Machac added to a miserable 2024 start for former number three Stan Wawrinka with the youngster defeating the 38-year-old Swiss 7-6 (7/3), 4-6, 6-2.
Defeat in just over two hours marked only the second first-round loss here for the veteran in 13 appearances.
Machac advances to a second-round meeting against France's Adrian Mannarino, the 21st seed.
French showman Gael Monfils lost just three games as he thrashed Australian Max Purcell 6-1, 6-2.
