Even though it includes winning his first ATP title, Borna Coric says he hasn't satisfied himself with his season.

The 20-year-old from Croatia is ranked No. 51, below the career-high No. 33 he reached in 2015. Coric leapt to attention when he defeated an ill Rafael Nadal in Basel in 2014, reaching the semifinals as a 17-year-old.

But he says that big win increased the pressure and attention on him when he was still developing as a player. "When I beat Rafa then and reached the semifinals in Basel, I didn't believe that was my level. I think my true level then was 60 or 70, not in the 30s," he told *Reuters*. "It put me on the map but made the expectations higher but my game was not there."

Coric, whose look and style of play has drawn comparisons to Novak Djokovic, had foot surgery in 2016 and was aiming to climb further back up the ranks this season.

He did win a first tour title, capturing Morocco's ATP 250 event. And he got two big wins, defeating Andy Murray in Madrid to reach the quarterfinals as a qualifier, and beating Alexander Zverev to reach the third round of the US Open. But there were not a lot of deep runs at other events.

"This year I had much bigger plans for sure. I wanted to finish in the Top 25," he said.

But Coric says he's developed his game this season and isn't concerned by the other players in his age group who have moved in front of him in the rankings. Zverev, 21, is No. 3 and has won a couple of Masters events.

"It’s not about catching Alex," Coric said. "I‘m just motivated by working hard and focusing on my own career."

Coric has reached the second round of this week's Paris Masters.