Novak Djokovic eased into the second round of the French Open but risked inflaming political tensions in his home region with a message about Kosovo.

After a 6-3 6-2 7-6 (1) victory over American Aleksandar Kovacevic, who is of Serbian heritage, Djokovic wrote on the camera lens: “Kosovo is the heart of Serbia. Stop the violence.”

Kosovo declared independence in 2008 but Serbia has never recognised that and violence broke out in the north of the country over the weekend after ethnic Albanian mayors were installed in Serbian-dominated areas, with NATO peacekeepers among those injured.