Grigor Dimitrov
Rafael Nadal of Spain (L) shakes hands with Grigor Dimitrov of Bulgaria after their men's singles quarter-final tennis match at the Australian Open 2014 tennis tournament in Melbourne January 22, 2014. REUTERS/Bobby Yip

Tennis legend Pete Sampras says that he will be astonished if rising Bulgarian athlete Grigor Dimitrov doesn't make it to the top five of the world rankings. The 14-time Grand Slam winner is confident that Dimotrov has the tennis skills to bring him to the top.

Rafael Nadal of Spain (L) shakes hands with Grigor Dimitrov of Bulgaria after their men's singles quarter-final tennis match at the Australian Open 2014 tennis tournament in Melbourne January 22, 2014. REUTERS/Bobby Yip

"If he's (Dimitrov) not in the top 10 or maybe in the top five by the end of the year, I'll be surprised," said Sampras when asked about his thoughts on Dimitrov as reported by Tennis World USA. Sampras went on and stated that Dimitrov's confidence in himself has increased. "He believes in himself more, he's got a great game," he added. "He really hits well and had chances against Rafa," said Sampras.

In the recently concluded 2014 Australian Open, Dimitrov gave Nadal a run for his money before the Spanish athlete won two tiebreaks in the quarterfinals of the tournament.

"He'll be right there, he's very good," said Sampras. "I don't know if he's quite ready to be competing for Grand Slam titles just yet - Novak and Rafa, I see those guys battling this year," he added.

However, Sampras thinks that Dimitrov could eat more and get heavier. "He's a pretty thin guy and I think he's working on trying to get some more muscle and get in better shape," he said. "He knows it, so he's working on it," said the retired American tennis legend. "He's only 22, so he's got a little time to get a little stronger, but he's on his way," said Sampras.

Dimtrov reached his career-high singles ranking after making his first-ever quarterfinals appearance in a Grand Slam tournament. He currently ranks 19th in the world. After competing in the 2014 Australian Open, Dimitrov was supposed to play in the Association of Tennis Professionals' (ATP) tournament in Zagreb, but he had to withdraw because of an injury.

"I really wanted to win the title in Zagreb, but unfortunately I have to pull out due to an injury," said Dimitrov. "I have very good memories from the tournament and from the city," he added. "I hope I will have more chances to be there in the future," he said.

Dimitrov's next tournament, given that he recovers from injury, is the ABN AMRO tournament in Rotterdam which starts on Feb 10.