Novak Djokovic's love affair with Rome continued as the five-time champion picked up his 60th victory at the Italian Open with a 6-3, 6-2 success over Aslan Karatsev on Tuesday. Ons Jabeur eased into the second round with a straight sets win over Sorana Cirstea but US Open champion Emma Raducanu was forced to retire from her first round against Bianca Andreescu, still struggling with a back injury she picked up in Madrid last week. World number one Djokovic has never lost before the quarter-finals at the tournament and is now just three victories shy of joining the 1,000 match-wins club. "He probably has the biggest calf we have in tennis. Very strong guy, just solid from the baseline," Djokovic said of the 35th-ranked Karatsev. "You never know with him. If he's feeling the ball, he can be very dangerous because he stays so close to the line, puts pressure on his opponents."