Nothing should faze Dominic Thiem in the week's Rio Open on clay.

He beat Rafael Nadal _ the king of the surface _ last week in the semifinals in Buenos Aires, and then won the event for his fourth clay-court title.

"Both things gave me a lot of confidence, but after the match with Nadal I wanted to give everything to win the tournament," Thiem said Tuesday after defeating Pablo Andujar of Spain 6-3, 6-4 in the first round of the Rio Open on clay.

"The win against Rafa would have been worth only half if I had lost the final."

The 22-year-old Austrian is the youngest player in the ATP top 20. He's seeded No. 5 in Rio and Nadal _ seeded No. 1 _ told reporters in Rio that if Thiem "keeps improving he's a candidate to achieve great things."

Several reporters told Thiem what Nadal said.

"It means a lot to me," he said. "He's the best clay-court player of all time and overall he's one of the best players of all time. When you hear something like this from him, it means a lot."

Nadal got a fast start in Rio running away from fellow Spaniard Pablo Carreno Busta x-x, x-x in his first-round match.

Nadal won gold in Beijing in 2008 but missed London with an injury. Despite being asked about it repeatedly, he’s staying away from talking about the Rio’s Olympics in six months.

"The Olympics is a very important event, a very special one, and I'm going to try my best when the Olympics arrive,” Nadal said. “But for now I'm playing the ATP tournament in Rio. That's the most important thing for me." I don't want to say it's the most important event for me, because I would be lying. My most important event now is Rio de Janeiro. Then it's going to be Indian Wells and Miami.

In other key results on Tuesday, No. 2 David Ferrer defeated Nicolas Jarry of Chile 6-3, 7-6 (3) to reach the second round.

Federico Delbonis of Argentina upset sixth-seeded Jack Sock of the United States 7-5, 6-1.

No. 3 Jo-Wilfried Tsonga of France and Nadal were playing their matches late on Tuesday. Tsonga faces Thiago Monteiro of Brazil and Nadal gets fellow Spaniard Pablo Carreno Busta.

On the women’s side, top-seeded Teliana Pereira of Brazil was knocked out in the first round as Petra Martic of Croatia advanced 6-3, 7-5.

Pereira’s early loss is a blow for the women’s side of the combined WTA-ATP event on outdoor clay. She is only ranked No. 43 but gave local organizers a hometown favorite.

In another early match Tuesday, second-seeded Johanna Larsson of Sweden defeated Lourdes Dominguez Lino of Spain 7-5, 6-4.