Grigor Dimitrov of Bulgaria returns the ball during his men's quarter-final match against Novak Djokovic of Serbia at the China Open tennis tournament in Beijing, October 3, 2014. REUTERS/Jason Lee
Grigor Dimitrov of Bulgaria returns the ball during his men's quarter-final match against Novak Djokovic of Serbia at the China Open tennis tournament in Beijing, October 3, 2014. REUTERS/Jason Lee REUTERS

Defending champion Grigor Dimitrov has booked his spot in the quarterfinals of the the 2014 If Stockholm Open. The 23-year-old Bulgarian has defeated Teymuraz Gabashvili of Russia, 7-5, 7-6 (4) in the second round on Oct. 15.

The match was a tough battle for Bulgaria's most successful tennis player. Dimitrov was put under pressure in both sets but he just needed to focus on good rhythm to seal his victory. He only needed one match point to win in two straight tie-breaker sets.

Dimitrov has equalled their head-to-head to 1-1. Their first meeting was dated all the way in 2011 on the US Men's Clay Court Championships in Houston. Dimitrov was defeated by the Russian in straight sets, 6-7, 3-6.

Dimitrov will be playing against Jack Sock of the U.S. in the quarterfinals. Dimitrov has never played against sock in the past.

Sock has reached the quarterfinals after defeating Frenchman Jeremy Chardy and Andrey Golubev. He has a 24-18 record in the current season. Sock is expected to break the top 50 of the world rankings come Monday.

Sock has praised Dimitrov for playing "unbelievable tennis" since winning the Stockholm Open in 2013. "He's jumped up the rankings pretty high, so I'll have to play my best to win," Sock said via ATP's official website.

"I'll take a full match from start to finish of my A-game, hopefully I can bring it and it will be the first of many battles."

Meanwhile, Dimitrov has previously revealed his longing to qualify in the Barclays Association of Tennis Professionals (ATP) World Tour Finals in London. He said that his goal is to play good tennis until the end of the season.

So far, only Roger Federer, Novak Djokovic, Rafael Nadal, and Stanislas Wawrinka have qualified in the event. Four more slots are up for grabs. It's a tight race for Milos Raonic, Andy Murray, Marin Cilic, David Ferrer, and Dimitrov, who are all careering the final slots. Dimitrov has fallen to the 11th rank behind Murray. The Bulgarian athlete will have to defend his title or at least make it to the semifinals to gather points on the ATP race to London.