By Gregory Blachier

MONTE CARLO (Reuters) - World number one Novak Djokovic said his years in the sport helped him switch off his emotions to beat Robin Haase and reach the semi-finals of the Monte Carlo Masters on Friday, a day after learning of the death of his grandfather.

The Serb, had some trouble focusing as he let Dutchman Haase recover from 4-1 down to 4-4 in the first set but wowed a supportive crowd as he went on to win 6-4 6-2.

"Today was a bit better, but still a lot of emotional ups and downs throughout the match," Djokovic told reporters, having only issued a statement on Thursday after beating Alexandr Dolgopolov.

"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 semi-finals, which is big result for me under the circumstances."

"Over the years, I've learned whenever I play tennis to kind of switch off from everything else. You get that mindset and that ability to switch off when you dedicate a lot of time to this sport," added the Wimbledon, U.S. Open and Australian Open champion.

"I'm a professional, and life goes on. I know that I cannot change anything now," he calmly said.

Djokovic, who is chasing Rafael Nadal's French Open crown, will play Czech Tomas Berdych in the semis.

Having described his grandfather as "my hero and a fighter... who is always sending me lots of positive energy" after winning in Miami, Djokovic said he was still feeling his support.

"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," he said.

(Editing by Alison Wildey)