Nadal rallied to beat Juan Martin del Potro 4-6, 6-3, 6-4 and win the BNP Paribas Open after Sharapova claimed her first title of the year, 6-2, 6-2 over Caroline Wozniacki in the women's final on Sunday.
Nadal improved to a career-best 17-1 on the year, including 14 straight match wins since returning in early February after a seven-month layoff because of a left knee injury.
He's won three titles—two on clay while runner-up in another on his favorite surface—and now his first on hard courts since Tokyo in October 2010. He had lost six previous finals on the surface.
"That's makes emotional week for me," he said. "Very important victory for me, winning against the best players of the world on a surface that is good for them."
Sharapova, runner-up here last year, won her first Indian Wells title since 2006. She and Nadal each earned $1 million.
"It's nice to hold up that trophy after so many years," she said.
The victories moved up both players in this week's rankings. Nadal is No. 4 and Sharapova is No. 2 behind Serena Williams.
"Number 1 is a great number," Sharapova said. "But I think at this point in my career, titles and Grand Slams are just a bigger priority."
Nadal won his 600th career match and broke a tie with Roger Federer for most career
Nadal defeated Federer in straight sets in the quarterfinals, then took out Tomas Berdych in two sets in the semis. Against Del Potro, Nadal rolled to an early lead in a match that was marked by several momentum swings.
Nadal served three love games in the third set, capping his last one with a 123-mph ace that gave him a 5-3 lead.
Del Potro came from love-40 down and fought off three match points to hold at 5-4. But Nadal served out the match, dropping just one point in the final game of the 2 1/2-hour match in the desert heat.
"I try to put the match in a little bit slower rhythm and waited for the right moments to go for the point and worked well," he said. "Del Potro is a fantastic player, so it's not easy to change the dynamic of the match like this."
Del Potro saved three break points to lead 1-0 in the third. Nadal held at love, taking three games in a row for a 3-1 lead that he never gave up.
After falling behind 3-0, Del Potro won eight of the next nine games to claim the opening set and take a 2-0 lead in the second.
"I was wrong in strategy for moments, something that for me is not usual, because normally I can have mistakes with the shots," Nadal said, "but with the tactics and how I have to manage the points, how I have to play the points, normally I am right."
Del Potro went up 3-1 before Nadal won the final five games and the set 6-3 on a 105-mph ace that capped a love service game.
After Nadal picked himself up, he hugged Del Potro, then trotted behind the baseline to clasp hands with billionaire tournament owner Larry Ellison of Oracle Corp. before falling to his knees near the net and raising his arms in celebration. Nadal playfully took a bite out of the Baccarat crystal trophy.
Del Potro came up short in his bid to beat three Top-10 players in the same tournament for the second time in his career. He defeated No. 3 Andy Murray and No. 1 Novak Djokovic in three sets apiece in becoming the second Argentine since Guillermo Villas in 1977 to reach the final here.
Sharapova dictated from the opening game, when she broke Wozniacki at love with groundstrokes that had the Dane running from side to side. Sharapova faced just two break points on her serve in the nearly 1 1/2-hour match.
"I always felt like I was always a foot ahead, especially with the breaks," she said. "I was able to serve well today, and that helped me."
The victory gave Sharapova at least one title for 11 straight years dating to 2003.