- Tag results for MIAMI
Nadal dethroned Switzerland's Roger Federer, a 20-time Grand Slam champion, who fell to second place following his loss in the first match of the Miami Open last month.
John Isner finally put an end to his ATP Masters final agony on Sunday, winning the Miami Open for the first time.
Stephens became the final women's champion on the picturesque island by beating Jelena Ostapenko 7-6 (5), 6-1 Saturday.
It was a phenomenal effort from the American who blasted down 13 aces and took just one hour and 23 minutes to floor Argentina's Del Potro and book his place in Sunday's final.
Kevin Anderson's quarter-final jinx struck again as Spain's Pablo Carreno Busta sent the sixth-seeded South African out of the Miami Open with a 6-4, 5-7, 7-6 (8/6) triumph.
The reigning US Open champion, who booked her place in the final with a 3-6, 6-2, 6-1 triumph, just 18 days after beating the Belarusian in straight sets in the second round at Indian Wells.
Del Potro raised the roof as he came from behind to beat Milos Raonic 5-7, 7-6 (7/1), 7-6 (7/3) and power into a Miami Open semi-final clash with American John Isner.
Collins pulled off an almighty shock at the WTA Miami Open, sending Venus Williams crashing out 6-2, 6-3 to reach the semi-finals.
Ostapenko was too strong for Svitolina in last year's Wimbledon round of 16 and it was more of the same on the Miami hardcourts as the Latvian sixth seed advanced 7-6 (7/3) 7-6 (7/5).
The big-serving 32-year-old Americans fired 12 aces to dispatch 19th-seeded Chung in only 68 minutes and within touching distance of his first ATP Masters title.
Kevin Anderson swept aside Frances Tiafoe while Nick Kyrgios bowed out of the tournament after going down to Alexander Zverev Jr.
Juan Martin del Potro sent his devoted fans home happy by powering into the ATP Miami Open quarter-finals with a 6-4, 6-2 triumph over Serbian Filip Krajinovic.
American Sloane Stephens had cause for a double celebration after beating Germany's Angelique Kerber 6-1, 6-2 to reach the WTA Miami Open semi-finals.
Yuki will be replaced by World No.246 Prajnesh Gunneswaran for the tie which will be held in Tianjin, China on April 6-7.
Kyrgios moved into the fourth round of the Miami Open despite admitting he's lacking the match fitness to properly compete for the title.