Rafael Nadal entered his Barcelona Open Banc Sabadell semi-final on Saturday perfect from that stage on at the ATP 500 tournament (22-0). But despite losing to Dominic Thiem in straight sets, the 11-time champion leaves his home event with his head held high.

“After this week my confidence is back,” Nadal said. “I really believe that I made very good improvements to create a good base to try to achieve my goals during the next couple of weeks."

It’s just the third time that Nadal has not won either Monte-Carlo or Barcelona in the same year (2014-15) going back to 2005. But Nadal knows that he did not give away the match. Instead, Thiem took it.

“He played great. He did all the things that he had to do very well and with big success. I am happy the way that I played from the baseline. Starting the point in good position or in bad position, changed a lot... but the rest of the things have been positive and as I said before, congrats to him, he played great,” Nadal said. “He's a great guy and great player and I'm happy for him. I wish him all the best.”

Last week, Nadal lost in the semi-finals of the Rolex Monte-Carlo Masters against Fabio Fognini. That was perhaps a more surprising defeat since Thiem has now beaten the Spaniard on clay in four consecutive years. Fognini has two clay-court wins against Nadal.

"[It’s a] big difference. Against Fognini I played the worst match probably in 14 years on clay. Today I played a good match of tennis. It [was] a good level of tennis this afternoon. I played against a great opponent,” Nadal said. “Fognini is a great opponent too but I was not a competitive player. Today I was competitive, and I enjoyed the match. I really felt [that I was] competitive for the first time in a way that I want to feel myself. And as I said before I am happy and I am confident that I made a big improvement this week."

Nadal knows there are things he could improve even more. The World No. 2 won just 43 per cent of his second-serve points against Thiem, while the Austrian captured 69 per cent of his second-serve points.

“The serve [was] an important part of the match this afternoon,” Nadal said. “I didn't serve well at all, especially the second serve. So when I started to miss the second serve, I really lost a little bit of the confidence on trying to go for a good first serve, because I was without confidence on the second, so that affects the first."

Thiem (4-7) joins World No. 1 Novak Djokovic (7-16) as the only players to defeat Nadal on clay at least four times. The 25-year-old recently won his first ATP Masters 1000 title (Indian Wells) on a hard court. So when a reporter asked Nadal if Thiem could one day climb to the top of the ATP Rankings, the Spaniard did not dismiss the notion.

“Why not? Depends. Everybody can be No. 1. Not everybody, but there are a couple players who can be No. 1. It is not an easy thing. But of course it depends on the results he will be able to have. He's a good player. He's a hard worker. So I would love to see him [be] No. 1,” Nadal said. “I like him in all terms, as a tennis player, as a hard worker, as a person. So I wish him all the very best for his future, but not everything. I hope to be ready to compete against him and to beat him in the next couple of weeks.”