Djokovic extends run

The second seed had a helping hand from opponent Victor Hanescu, who retired in the third set on Court Philippe Chatrier when trailing 4-6 1-6 3-2.

The Romanian had received treatment to his left thigh throughout the third set and at 30-0 down in the sixth game decided he could no longer continue.

Djokovic has not lost a match since his semi-final against Roger Federer at the ATP World Tour Finals in London in November but former US Open champion Del Potro looked impressive in his 6-3 6-2 6-4 win over Blaz Kavcic.

Former world No 1 Roger Federer gave French wild card Maxime Teixeira a grand slam lesson, winning 6-3 6-0 6-2.

Third seed Vera Zvonareva came back from match-point down to defeat ailing German Sabine Lisicki 4-6 7-5 7-5 in the second round of the women’s.

The German collapsed to the clay in distress and had to be carried from court on a stretcher at the end of the match.

World No 1 Caroline Wozniacki needed almost two hours to grind out a 6-3 7-6 (8/6) victory over near namesake Aleksandra Wozniak.