World number two tennis player Serbian Novak Djokovic defeated Romanian Adrian Ungur during their match at Serbia ATP Open tournament in Belgrade.
Djokovic won 6-2, 6-3 in less than 70 minutes on the clay.
It was the 25th victory of Djokovic registered without a loss in this season, the best start to an ATP tour since Ivan Lendl in 1986.
Slovenian Blaz Kavcic, is the quarter-final opponent of the 23-year-old Djokovic on Friday.
Djokovic, who earlier this month was forced to pull out of the Monte Carlo Masters blaming a knee injury, said he was not burdened by a record-start to the season.
He was his country’s key player as he led Serbia to their first-ever Davis Cup title in Belgrade last December.
The number two said he had an ambition to win at least one more Grand Slam this year and get himself involved in fight for the number one position, currently held by Rafael Nadal.