Djokovic straight through again, with effort

Novak Djokovic of Serbia celebrates after defeating Andreas Seppi of Italy in their third round match at the U.S. Open Championships tennis tournament in New York, September 4, 2015. REUTERS/Adrees Latif

NEW YORK (Reuters) - Top seed Novak Djokovic notched another straight sets win but was given more of a workout in a 6-3 7-5 7-5 victory over Italian Andreas Seppi in reaching the fourth round on a hot, humid Friday at the U.S. Open.

Djokovic had lost just 10 games through the first two rounds and despite beating 25th-ranked Seppi in all 10 of their previous meetings, the 28-year-old Serb needed a tiring two and a half hours at Arthur Ashe Stadium to reach the Round of 16.