Novak Djokovic had only words of praise for his opponent after being beaten in straight sets by fellow Serbian Dusan Lajovic at the Srpska Open in Banja Luka.

Lajovic bested the 22-time grand slam winner 6-4 7-6 (8-6) on Friday in the quarter-finals, dumping Djokovic out against the odds.

The key for Lajovic was saving break points, managing to rescue an incredible 15 of 16 that Djokovic earned.

Speaking after his loss, the number one seed said: "Dusan is a fantastic person, great guy. Someone I've known for a very long time, since he started playing professional tennis. So many times on the Davis Cup team together, trained together. I'm happy for him, to be honest.

"I know this is an important win for him considering the last 12 months that he's been through, it's not been easy for him. He's playing well and he deserved to win today."

It was the first time Djokovic had lost to a compatriot since Janko Tipsarevic beat him at the ATP Masters 1000 in Madrid in May 2012.

Lajovic declared it his biggest ever victory, and reciprocated the words of kindness from Djokovic.

"I'm overwhelmed, it is the biggest win of my career," Lajovic said on-court. "The emotions are very mixed because I'm playing here in front of the home town and I'm also playing against Nole, who is a good friend and he's a hero of our country.

"Beating him, it's something that I didn't even think is going to be possible, but it happened."

Lajovic will face another Serbian in the semi-finals in Miomir Kecmanovic, who beat Jiri Lehecka 7-5 6-0.