World number one Novak Djokovic maintained his serious approach to the Mutua Madrid Open to go through to the semi-finals on Friday night, beating Milos Raonic 6-3, 6-4 on centre court with the roof still closed against the elements.

Djokovic, the top seed in this year’s tournament, is the only player yet to drop a set all week and will face sixth seed Kei Nishikori for a place in the final.

“My return was one of the keys to the game,” said the Serbian in his post-match press conference after racking up 10 break point opportunities in just nine games facing the fearsome Raonic serve. “The idea was to get as many balls back into play as I could, to not give him too many free points on his serve… that’s where I build confidence from. I’m very satisfied with the level I showed. When I found myself in trouble I was able to serve well and hit good forehands to get out of it.”

Djokovic, who had beaten Raonic in each of their previous six meetings, analysed the difficulty in playing against the Canadian: “It’s not easy to play against someone who serves so hard, but I was solid on the return. I covered most of the angles, I always made him play an extra shot. That was the objective.”

Now into the last four at the tournament, Djokovic will play Nishikori on Saturday as he seeks to reach a second final at the Mutua Madrid Open. “It will be a completely different game to today,” said the world number one. “Kei doesn’t serve as hard as Milos but he is a lot quicker moving around the court and he plays very aggressively. He has been in the final here before and I know I’m playing a player with a lot of experience. He has played in big games on many occasions and we know each other well. I’ll try to mix up the tempo and play a good game.”