Rafael Nadal reached the Olympic Games quarter-finals on Thursday, winning the first of 10 matches he will need to sweep in just four days if he is to secure triple Rio gold.
The 2008 champion defeated Gilles Simon 7-6 (7/5), 6-3 for his eighth win over the Frenchman in nine meetings.
Nadal, a 14-time major winner, is playing in his first tournament in two months after a wrist injury caused an early withdrawal from the French Open.
After torrential rain wiped out Wednesday's entire programme, the 30-year-old faced an epic test of his fitness and stamina.
He heads out to Court Three later Thursday with Marc Lopez to take on Canada's Daniel Nestor and Vasek Pospisil with a spot in the men's doubles final at stake.
Then, in the evening, the Spaniard readjusts his compass for his first match in mixed doubles of his career.
Nadal is partnering French Open champion Garbine Muguruza against Lucie Hradecka and Radek Stepanek of the Czech Republic.
Simon's only win over Nadal came eight years ago, but he proved a thorn in the side of the Spaniard in the opening set.
He broke for 2-1 before the Spaniard levelled at 2-2. Nadal was quickly 4-2 up but the dogged 15th seed hit back in the seventh game.
Nadal swept to a 5/1 lead in the tiebreaker but he still couldn't shake off the 31-year-old who clung on for 5/5 before the former world number one grabbed the opener.
The second set started far more comfortably with Nadal grabbing a double break to stretch to 4-0 on his way into the last-eight.
After Wednesday's deluge, the tournament was playing catch-up with the women's singles quarter-finals to be completed.
Elina Svitolina, the conqueror of defending champion and world number one Serena Williams, is to face Petra Kvitova while Monica Puig meets Laura Siegemund.
In the bottom half of the draw, second seed and Australian Open champion Angelique Kerber tackle Britain's Johanna Konta.