WIMBLEDON, England—Grigor Dimitrov, who lost in the third round of Wimbledon to Richard Gasquet, says he is at a different stage of his career, one filled with more pressure as a known quantity. He reached the semifinals of Wimbledon last year; since then, Dimitrov reached the fourth round at the 2014 U.S. Open and the 2015 Australian Open, and lost in the first round of the 2015 French Open.

Dimitrov says that backing up his performances has been harder than achieving them for the first time.

“Well, I'm 24. I don't consider myself that young anymore,” Dimitrov said. “Obviously with age, you sort of think you're getting older. I think last year was an eye-opener for me. It showed me what I was capable of. I fell into a rhythm that I always wanted to. But I knew it was very hard to sustain.

"That's why I think the top guys are what they are, because they're always backing themselves up. I think that's why it's one of the hardest things for me that I've learned—to cooperate with the situation that I'm not playing as good as last year,” he said.

Dimitrov added that he is working on becoming more consistent and playing with more confidence.

“Also I think it comes down to a bit of mental strength, something that you really need to sort of look at it and maybe see what you can do different," he said. "For me, it's always been an exciting time, especially when I'm playing a tournament. I'm trying not to think about any of those things.”