Serena Williams battled blustery conditions to reach the Wimbledon second round with a 7-5 6-3 victory over Dutchwoman Arantxa Rus.
Seven-time champion Williams, the 25th seed after having a baby in September, did not have it all her own way against the left-hander's formidable forehand.
After winning the first set when Rus sent a forehand long, she had to fight back from a break down in the second.
Williams faces Bulgarian qualifier Viktoriya Tomova next.
The 36-year-old American, tipped for another title in a wide open women's draw, was not happy with her performance in what is her second Grand Slam tournament since her return to the WTA Tour.
She needed six match points before finally sealing the victory when world number 105 Rus netted a backhand.
A straight-set win in the first round at Wimbledon is nothing new for Williams, but in playing her first match here since 2016 she said she was still finding her bearings on grass.
Now addressed by the umpire as "Mrs Williams" and ranked 181 in the world, the rustiness in her game showed when she left the crowd laughing as she tried and failed to pat the ball off the ground and on to her racquet before a serve.
In gusty conditions on Court One, where the players' towels blew off the chair, fans held on to their hats and serve tosses were repeated, Williams made 29 unforced errors.
"I wasn't quite used to that level of wind," she said. "Looking back I'm glad I had that wind as in the future I will be able to play a bit better.
"I'm happy to get through that, I didn't play my best but I will get there."
Serena Williams took a tumble but got up to move into the second round
When Williams returned to Grand Slam tennis at the French Open in May, she was sporting a black catsuit to help her deal with blood clots.
That was replaced at Wimbledon with a white long-sleeved dress and flesh-coloured compression tights, but what were still apparent were her powerful shots that took her to the Roland Garros fourth round before she was forced to pull out with an injury that affected her serve.
During the warm-up against Rus she repeatedly circled her serving arm but she managed five aces and showed no sign of it still bothering her.
"I took a lot of time off with serving. I just started serving when I got here," she said. "My serve is a little playing catch-up but doing better than I hoped."
A slip on the grass did not affect her game, but her errors did keep her on the court longer than necessary.
A noisy first set, where she roared when she hit winners made way for a quieter second set and when Rus' backhand mistake handed her victory there were no wild celebrations.
"I feel like I maybe was just overly anxious and overly, over-trying, overdoing it [earlier]," she said.
"But towards the end, I definitely was more calm, just making my shots, just playing a more serene game."
Williams has been seeded here despite her lowly ranking, which is in contrast to Victoria Azarenka last year after the Belarusian's return from maternity leave.
Former world number one and two-time Australian Open champion Azarenka, who beat Russian Ekaterina Alexandrova 7-6 (7-4) 6-3 to reach the Wimbledon second round on Monday, said that the fact she and Williams had been treated differently was leading to a healthy debate.
"I think it's an important conversation that has been started," the 28-year-old said.
"This conversation has led to numerous meetings, numerous occasions where we are discussing the rules and how can we be a leader in sports to have the best maternity policy.
"A couple of days ago we had a big meeting, and I feel like we are moving in a really good direction. I feel that our voices, as a player council, are heard. We do implement things that are going to be important for players.
"But my main thing is that it has to be for everyone, and the rules have to be applied for everyone. So that is one thing that we haven't come to the conclusion yet, but it's coming."