Grigor Dimitrov is career is on the rise and that seemed to have put a wedge between him and his uber successful girlfriend Maria Sharapova. His ambition at US Open 2014 is not just to win the tournament, but also to win back Maria Sharapova. It looks like the world number 8 is determined to do some serious damage in Flushing Meadows this year!

The big rumor this week was that the couple has unfollowed each other on Twitter. Grigor Dimitrov and Maria Sharapova has had such spirited exchanges on the social media medium that it’s hard to imagine why they would choose to unfollow each other… unless their relationship is on the rocks!

Still, Grigor Dimitrov only had nice things to say about his girlfriend of two years during his interview with Vogue.

“She is very strong-minded and knows what she wants,” he says admiringly. “It’s why she’s the best at what she does.”

The world number 8 also revealed how they started dating. “I was the initiator, pretty much,” he admits. “I sent her a funny email and she replied, and back and forth, and that was it.”

Technology, which launched their romance, also seems to mark their downfall. Grigor and Maria are both extremely busy with their eyes on the prize at US Open 2014, but could there be other reasons to their silence?

Usually before big tennis tournaments, the couple are caught strolling the streets together. But at this year’s US Open, they kept their social commitments and training apart.

Grigor Dimitrov is getting a lot of traction at the Flushing Meadows this year.

“I think we’re seeing a bit of a seismic shift,” ESPN commentator Brad Gilbert said after this past Wimbledon, in which the 23-year-old Bulgarian reached the semifinal. “All the younger guys want to see somebody of their own generation win a Slam, and I think Dimitrov is the closest. He’s a tremendous all-rounder.”

“I was playing against a future star,” Novak Djokovic said after a game against Grigor Dimitrov.

Meanwhile, his girlfriend Maria Sharapova has been busy with her business ventures with Supergoop and Sugarpova. Her ambition matches his own, though she has much more experience on the court and in business.

“I knew that I wanted to go big,” Grigor said to Vogue. “I think mental preparation is really important. Every day you’ve got to imagine your goal. And my goal is to really do damage at the U.S. Open.”

We bet that Grigor wants to win not only the tournament, but Maria Sharapova’s heart. She only dates winners so it’s in his best interest to win big this year at the Flushing Meadows.