The romantic relationship between tennis power couple Maria Sharapova and Grigor Dimitrov could be in jeopardy after netizens noticed that the two unfollowed each other on micro-blogging site Twitter.

According to International Business Times, the rumors regarding Sharapova and Dimitrov's breakup started when some of their followers found out that their tennis idols allegedly unfollowed each other on Twitter.

Dimitrov has been dating the 27-year-old Russian beauty for two years now, and the fast-rising Bulgarian hasn't hesitated expressing his true feeling towards Sharapova whether on press conference or on social-networking sites.

There have been speculations that the romance between the two tennis stars is currently in a limbo, which appears to be reasonable explanation why the two unfollowed each other.

Then again, there's no assurance if they really intended to break their connection (at least on Twitter) or they just don't want to follow each other since they have been hanging around all this time.

"Both Sharapova and Dimitrov have built a significant story following on Twitter, but they do not follow a whole lot of people so it is pretty much easy to find out who the people they are following on the social networking platform," the International Business Times reported.

"Sharapova and Dimitrov follow 60 and 64 Twitter users, respectively, and neither one was on each other's following list. It is unclear whether Sharapova and Dimitrov unfollowed each other just recently or if they were not really following each other since they got together."

This isn't the first time Sharapova and Dimitrov were dragged into breakup rumors. Last February, there are reports that the two split, as the two posted tweets believed to have double meanings, according to their fans. It happened after the Bulgarian had a date with rising star Genie Bouchard in Acapulco to kickstart a tennis tournament in the tourist spot.

If rumors are true, Sharapova and Dimitrov should set their heart problem aside for now as they compete for the last Grand Slam title of the year at the US Open championships in Flushing Meadows, New York.

Sharapova, the no.5 seed in the women's singles competition, will gun for her second US Open crown and sixth in her career, while Dimitrov aims for his maiden major title.