Stan Wawrinka became the latest big name to suffer an early exit from Wimbledon as he went down to tournament debutant Reilly Opelka in the second round on Wednesday even as the unlikely pair of Andy Murray and Serena Williams face recent Grand Slam doubles winner in their first match together.
Wawrinka - who has never won Wimbledon and has now failed to reach the third round for four straight years - looked on course for a routine win after fighting back from losing the first set.
But Opelka rallied to clinch a 7-5 3-6 4-6 6-4 8-6 victory in three hours and 13 minutes.
World number 19 Wawrinka started Wednesday's encounter on No.2 Court in sluggish fashion, with the American breaking serve in the 11th game.
Opelka could not keep up his form in the next two sets, however, but the 2015 boys' champion broke the Swiss star – seeded at 22 - again to force a fifth set.
And after Opelka held his nerve on serve to edge into a 7-6 lead, the 21-year-old made the most of three match points when Wawrinka sent a weak forehand into the net.
Wawrinka joins the likes of Alexander Zverev, Stefanos Tsitsipas and French Open finalist Dominic Thiem in slumping out in the opening rounds.
Opelka, meanwhile, will face Robin Haase or Milos Raonic in his next match.
In the mixed doubles, the eye-catching team of British star Murray and American Williams boast impeccable singles credentials but have plenty to prove as a partnership and will begin with a clash against Germany's Andreas Mies and American-born Chilean Alexa Guarachi.
Guarachi is a doubles specialist who has spent much of her career on the second-tier ITF tour, but Mies was a French Open champion last month with compatriot Kevin Krawietz.
The winners of that match will tackle France's Fabrice Martin and American Raquel Atawo in round two, after the 14th seeds were given a first-round bye.
Jamie Murray teams up with Bethanie Mattek-Sands in another potent British-American combination, one that delivered grand slam success when they won the US Open together last September.
They start against Britons Joe Salisbury and Katy Dunne, with third seeds Mate Pavic and Gabriela Dabrowski waiting in round two.
- @serenawilliams and @andy_murray— Wimbledon (@Wimbledon) July 3, 2019
- @jamie_murray and @matteksands
- @Venuseswilliams and @FTiafoe
- @CocoGauff and @Jay27798
We've got a bumper mixed doubles draw on our hands this year...#Wimbledon pic.twitter.com/ysRV4iOGlr
The Murray brothers feature in opposite halves of the draw so could not meet across the net until the final. Serena and Venus Williams could go head to head in the semi-finals.
Venus has never won the Wimbledon mixed doubles, unlike Serena who partnered Max Mirnyi to the title in the 1998 championships.
Venus will be looking to achieve the feat at the age of 39, pairing up with fellow American Frances Tiafoe, a 21-year-old talent, and they play the unheralded British duo of Scott Clayton and Sarah Beth Grey.
The surprise singles conqueror of Venus Williams has also entered the mixed doubles, with 15-year-old American Cori Gauff pairing up with Britain's Jay Clarke.
Gauff and Clarke tackle 42-year-old Swede Robert Lindstedt and former French Open singles champion Jelena Ostapenko.
Finland's Henri Kontinen and Briton Heather Watson won the mixed doubles at Wimbledon in 2016 and were runners-up a year later. On their latest SW19 mission, they play Marcelo Demoliner and Abigail Spears.