Novak lifted the trophy twice in the capital of Spain, in 2011 and 2016. Last year he beat Andy Murray in the final (6-2, 3-6, 6-3).
Four-time former champion finished runner-up at Rome Masters last year, following a 3-6, 3-6 defeat to Andy Murray in the final.
Novak won his first French Open title in 2016 and completed historic career Grand Slam. He outplayed Andy Murray in the epic final (3-6, 6-1, 6-2, 6-4).