Andy Murray has split from his coach Amelie Mauresmo, ending a groundbreaking two-year relationship during which the British star improved as a clay-court player but failed to add to his collection of Grand Slam titles.
Mauresmo, a former women's world No. 1, said "dedicating enough time along with the travel has been a challenge for me.''
The Frenchwoman gave birth to her first child in August and took six months off from coaching.
She was in Spain as Murray lost the Madrid Open final to Novak Djokovic on Sunday, but his new assistant coach, Jamie Delgado, took charge off the court.
"Working with Andy over the last two years has been a fantastic experience for me," said Mauresmo, who won the Australian Open and Wimbledon in 2006. "I've thoroughly enjoyed being part of the great team of people he has around him."
Murray became the first high-profile tennis player to hire a woman as a coach when he brought Mauresmo on board in June 2014.
By that time, he was already a two-time Grand Slam champion -- at the US Open in 2012 and Wimbledon in 2013 -- and had also won a gold medal at the London Olympics in 2012.
Under Mauresmo, Murray reached the final at the Australian Open in 2015 and '16, losing both times to top-ranked Djokovic. He won his first clay-court titles last year in Munich and Madrid.
"I'm sad about it but it just wasn't working," Murray told British newspapers in Rome. "There was not enough time spent together."
Murray revealed the pair made the decision together when they spoke in Madrid last Monday.
"Since Australia we only spent 10 days together, in Miami. For both of us I think if you have two and a half months and you only spend 10 days together -- and in those 10 days I was going through a tough patch in Indian Wells and Miami -- it makes things difficult because you need to work your way through those tough times together.
"We got together again just four days before the tournament and that just wasn't enough time. When I was playing my best with her coaching me, we were spending blocks of time together and that's not been happening lately. The weeks were less.
"You need a little bit more consistency so it was just acceptance that it wasn't going to work, and those periods apart were going to continue happening. Post Wimbledon and post the US Open, there were going to be periods when we were spending significant time apart."
Murray admitted he is open to the idea of appointing another female coach.
"My experience with Amelie was a good one," he said. "We would have liked to have won another Grand Slam in that time but I got my ranking back up from No. 11 in the world back up to No. 2 and had good results."
Murray was flying from Madrid to Rome for this week's Italian Open when the announcement of his split with Mauresmo was made Monday.
He had said in a statement released by his management company: "I've learned a lot from Amelie over the last two years, both on and off the court. She's been a calming influence in the team and we will all miss having her around.''
Murray felt the need to dismiss rumors of a fallout with Mauresmo in March after a three-set loss to Grigor Dimitrov at the Miami Open sparked speculation all may not be well between them.
Their partnership was also temporarily broken when the former women's world No. 1 took a break from coaching Murray after Wimbledon last year to give birth to her first child; Jonas Bjorkman, then an assistant on the world No. 3's coaching team, took the reins.
Bjorkman and Murray parted ways in December, however, with two-time Grand Slam winner Mauresmo returning ahead of the Australian Open.
Murray is heading into a busy period of the season, with the French Open, Wimbledon, Rio de Janeiro Olympics and US Open all in the next four months.
"I'll take some time to consider the next steps and how we progress from here," Murray said, "but I'd like to thank her for everything she has done. She's been an invaluable member of the team."
Information from The Associated Press was used in this report.