World number one Angelique Kerber kicked off her bid to return to the Wimbledon final with a 6-4, 6-4 win over Irina Falconi, while Roger Federer and Novak Djokovic prepared to start their All England Club campaigns.
With defending champion Serena Williams sidelined while she prepares to give birth to her first child, the race to lift the Venus Rosewater Dish is the most wide open in a generation.
Kerber, the 2016 Australian and US Open winner, is among the favourites after reaching last year's final.
The German has failed to maintain that form this season and her poor run culminated in an embarrassing French Open first round loss to Ekaterina Makarova last month.
But top seeded Kerber showed glimpses of her best form as she saw off American qualifier Falconi in 87 minutes on Centre Court.
The 29-year-old faces Belgian world number 88 Kirsten Flipkens for a place in the last 32.
"All the memories came back. It was amazing what happened last year," Kerber said.
"I'm happy to be back, but this year is completely different for me. I'm just happy I'm through the first round."
As the United States celebrated Independence Day, American 24th seed Coco Vandeweghe, the grand-daughter of a former Miss America, beat Mona Barthel 7-5, 6-2.
Australian qualifier Arina Rodionova, ranked 166th, saved seven match points before defeating Russian 16th seed Anastasia Pavlyuchenkova 3-6, 7-6 (8/6), 9-7.
Kiki Bertens, the Dutch 23rd seed, was beaten 7-6 (7/4), 7-5 by Romanian world number 63 Sorana Cirstea.
In the men's draw, French 22nd seed Richard Gasquet slumped to a 6-3, 6-4, 5-7, 6-2 loss against Spain's David Ferrer.
It was the first time Gasquet, a two-time Wimbledon semi-finalist, had lost in the first round since 2006.
Argentina's Juan Martin Del Potro, a Wimbledon semi-finalist in 2013, defeated Australian Thanasi Kokkinakis 6-3, 3-6, 7-6 (7/2), 6-4 as the 29th seed moved towards a potential third round classic against Djokovic.
Rising British star Kyle Edmund won for the first time at Wimbledon after four successive opening round losses.
Edmund, 22, beat compatriot Alex Ward, ranked 869th, 4-6, 6-3, 6-2, 6-1.
Later on Tuesday, Federer, chasing a record eighth Wimbledon title, starts his 19th All England Club campaign against Ukrainian world number 84 Alexandr Dolgopolov.
Having unexpectedly won the Australian Open in January before taking the clay-court season off to rest, Federer can lay down a marker to his title rivals by claiming a record 85th match win at Wimbledon.
That would take the 35-year-old past Jimmy Connors into sole possession of the first place on the day he makes his 70th Grand Slam appearance, equalling Fabrice Santoro's Open era record.
Three-time champion Djokovic opens his bid to regain the All England Club crown against world number 47 Martin Klizan of Slovakia.
Djokovic crashed out in the third round at Wimbledon last year and has endured the worst run of his career in 2017, the 12-time major winner losing in the second round in Melbourne and the quarter-finals in Paris.