Women's top seed Iga Swiatek was handed a tricky first-round test at Wimbledon as the world No. 1 was drawn against American Sofia Kenin on Friday.
Czech reigning champion Marketa Vondrousova, seeded sixth and in the same quarter of the draw as Swiatek, will open against Spain's Jessica Bouzas Maneiro.
Men's defending champion Carlos Alcaraz, seeded three, will start against Estonian qualifier Mark Lajal and finds himself in the same half of the draw as top seed Jannik Sinner.
Italy's Sinner plays German Yannick Hanfmann.
Britain's two-time winner Andy Murray was in the draw despite doubts over whether or not he will be fit after requiring surgery on a spinal cyst last weekend.
Murray, who will almost certainly be playing his final Wimbledon having said he plans to retire after the Olympics, will play unseeded Czech Tomas Machac.
Seven-time winner Novak Djokovic, the second seed who also has injury worries, was drawn against Czech qualifier Vit Kopriva. Djokovic is seeded to play Germany's fourth seed Alex Zverev in the semifinal.
Zverev begins against Spain's Roberto Carballes Baena.
Swiatek, whose five Grand Slam titles include four at the French Open, has not always found Wimbledon's lawns to her liking but the 23-year-old Pole will need to hit the ground running against Kenin, the 2020 Australian Open champion.
Her potential semifinal opponent would be 2022 winner Elena Rybakina who plays Elena-Gabriela Ruse in round one.
Women's second seed Coco Gauff will play in an all-American first round tie against Caroline Dolehide while third seed Aryna Sabalenka of Belarus, who Gauff could face in the semifinals, takes on American Emina Bektas.
Some other notable first-round draws in the women's singles include a clash of Grand Slam champions as Victoria Azarenka faces Sloane Stephens while British wildcard Emma Raducanu, the 2021 US Open champion, is up against Russian 22nd seed Ekaterina Alexandrova.
Britain's new men's No. 1 Jack Draper, seeded for the first time at Wimbledon, opens his campaign against Swedish qualifier Elias Ymer.
Play begins at the year's third Grand Slam on Monday when Spain's Alcaraz will open proceedings on Centre Court.
Vondrousova, who became the first unseeded player to win the women's singles when she beat Ons Jabeur in the final last year, will begin her title defence on Tuesday and will hope she has recovered from a hip injury sustained last week in Berlin.