World No. 6 Kei Nishikori came from a set down to defeat Viktor Troicki 5-7, 6-2, 6-3 in their Italian Open second-round match on Tuesday.

Although the 24th ranked Serb uncorked 10 aces in the Masters event, he was only able to win 41 percent of his second serves in a 1-hour, 55-minute match that left Nishikori gassed.

Nishikori, who has lost just twice this year to lower-ranked opponents, beat Troicki for the fourth time since the Serb won their initial encounter in Tokyo in 2010.