Grigor Dimitrov admitted that he is altering his strokes and strategy, which has affected his performances this year. The world No. 11 reached the semifinals in Brisbane, but lost to Roger Federer. Since then, the Bulgarian fell in the fourth round of the Australian Open to Andy Murray and exited in the second rounds of both Rotterdam and Acapulco.

"A little bit different since I have been working on a lot of things. I think it just takes a bit of time to really find that rhythm," said Dimitrov, who is coached by Roger Rasheed. "[My] game still needs to improve a little bit more, needs a bit of a sort of polish up….Usually it's very tough when you break a habit to come out there and play under the circumstances, under the pressure and all those kind of things. It's never easy to change it right away."

Dimitrov beat Nick Kyrgios in the second round of Indian Wells, 7-6 (2), 3-6, 7-6 (4), and will play Tommy Robredo next. In Acapulco, the 23-year-old had thrown his racket after he lost to another young player, Ryan Harrison, 6-0 in the third set.

"Every time I don't perform well there is always frustration in a way," said Dimitrov, who reached the 2014 Wimbledon semifinals. "I think I was a little bit overwhelmed with my frustration. There were a few unsettled parts outside of that…I had a little bit of a rough patch. I'm not going to lie for that. But things seem to be really bright right now. I fought hard for this match today. I mean, this is how I have been playing also lately, and especially last year I have been fighting a lot for a lot of matches."