Novak Djokovic happy with having his brother as assistant coach

Novak Djokovic moved into the semifinals of the Mutua Madrid Open on Friday after Marin Cilic withdrew with food poisoning. He will play either Roger Federer or Dominic Thiem for a place in the championship match.

Novak Djokovic, who is aiming for his third Madrid title, says his brother Marko Djokovic has been officially brought on as an assistant coach since he reassembled his team a little more than a year ago.

Marko Djokovic reached a career-high ranking of No. 323, and is now coaching at the Marbella academy where Novak Djokovic frequently trains.

"It's really nice to have a family member with me on the tour," Novak Djokovic told press at Madrid.

He cited his coach's desire to travel less because of his family.

"Marian [Vajda, his coach], it's hard for him to do, to travel full-time," Novak Djokovic said. "So I needed to have someone else and I found that at this point in my career and this time I'm the most comfortable with my brother next to Marian."

Novak Djokovic, who has previously had two coaches on his team, is enjoying the familiarity of working with his brother.

"Marko has been practicing with me so many times in our lives and playing doubles with me and then coaching me. It's a different feeling to be honest. But right now I'm used to it," he said. "At the beginning, it was kind of strange because I didn't know how I should behave towards him, you know. Sometimes I'm not so easy on the court, he's tolerating that and he's really amazing."

Novak Djokovic, who began the season by winning the Australian Open but has not reached a semifinal in three events since, suggested his game was improving again.

"I'm building slowly," he said. "I know what to do and the good thing is you always have an opportunity within a week or two weeks, three weeks, to rectify maybe certain things that you felt like were not working."

The Serb is still No.1 in the rankings.