Emotional Djokovic: My late grandfather is with me in spirit

(CNN) -- An emotional Novak Djokovic claimed his late grandfather was with him in spirit as he beat Robin Haase to reach the last four of the Monte Carlo Masters.

Djokovic learned that Vladimir has passed away hours before his quarterfinal against Alexandr Dolgopolov on Thursday but decided to play on.

And after his routine 6-4 6-2 win over Haase, from the Netherlands, he paid tribute to his grandfather.

"Today was a bit better, but still a lot of emotional ups and downs throughout the match," he was quoted as saying on the ATP Tour's website.

Djokovic puts grief to one side to down Dolgopolov

"But look, I'm playing tennis. I'm very satisfied that I was able to compose myself and get on the court and try to win matches. I got to the semifinals, which is big result for me under the circumstances.

Rafael Nadal answers iReporter questions

"I was very close to him, so it was a big loss for me and all the family. But he's with me, I know that, in spirit. I'm remembering only the nicest memories, and that's what gave me strength to play yesterday and today."

Djokovic will now face Tomas Berdych after the Czech knocked out No.3 seed Andy Murray, from Britain, 6-7 6-2 6-3 and the Serbian said his next opponent is a threat on any surface.

"He knows what it feels like to play on the big stage," he added. "Big ground strokes, powerful serve. He had a great match against Andy today. Hit incredible shots from baseline.

"It's a big challenge for me to see if I'm able to keep the focus throughout the whole match because this is the only way I can actually get a win against Tomas. We'll see if that's going to happen. I'll give my best."

Berdych said his approach against Djokovic would be the same that proved successful against Murray, who admitted the best player had won.

Former No.1 Clijsters to miss French Open with injury

"I'm going to do everything the same like I do before every game," Berdych said. "It's a day to play the No. 1 player in the world, which is always great. It's a semifinal, which is fantastic."

Djokovic is on course to meet defending champion Rafael Nadal in the final after the Spaniard maintained his incredible winning streak in Monte Carlo with a 7-5 6-4 victory over Poland's Stanislas Wawrinka.

Nadal's win was his 40th in a row at the tournament -- his last defeat came in 2003 -- and the world No. 2 said he is improving as the week goes on.

"Today was a difficult match," he said. "I had before the match big respect for this afternoon. He arrived for the match playing I think great.

"I am happy about the way that I played. I'm in the semifinals. That's fantastic news for me. I'm just looking forward to playing a good match tomorrow."

Nadal will now meet Gilles Simon after he won his all French clash with Jo-Wilfried Tsonga 7-5 6-4.