There were also wins for Thiemo de Bakker, Sam Querrey, Thomaz Bellucci and Michael Berrer.

BBC: Andy Roddick through to Cincinnati Masters second round

The other winners on Tuesday were Tommy Robredo of Spain, German duo Bjorn Phau and Michael Berrer, and Somdev Devvarman of India.

BBC: Janko Tipsarevic

Djokovic, who struggled past Germany's Michael Berrer in the first round, broke his opponent six times on his way to a 6-1 6-3 victory in one hour and 14 minutes.

CNN: STORY HIGHLIGHTS

Meanwhile, top seed Marin Cilic won his opening match at the BMW Open in Munich, moving into the second round as he completed a rain-delayed 6-4 6-2 victory over Michael Berrer on Wednesday.

CNN: Federer registers first clay win of 2010