Kyle Edmund has split with coach Fredrik Rosengren as the Swede announces his retirement to spend more time with his family.
The British number one drafted Rosengren into his coaching set-up in 2017 and Edmund has enjoyed the best form of his career with the Swede in tow.
Edmund wrote on Twitter: "Sad to announce Fidde [Rosengren] is retiring from the tour.
"You’ve been an integral part of the team over the last year and a half and together we’ve reached a top 15 ranking, a Grand Slam semi-final and won a title in Antwerp in October.
"I will be forever grateful, enjoy retirement."
The 24-year-old burst into the top 20 of the ATP rankings with a career-best semifinal run at the Australian Open last year.
He then reached his first ATP final in Marrakech in the spring, but was resoundingly beaten by then-355th ranked Pablo Andujar.
However, he ended his hoodoo with a title at the European Open in Antwerp later in the year, rallying from a set down in the final against Gael Monfils to triumph 3-6, 7-6(2), 7-6(4).
Edmund and Rosengren were visibly emotional in the aftermath and the world number 28 said at the time: "I'm just very happy obviously. A lot of hard work goes into this. It’s just emotion.
"You’ll always remember this one. I’m so happy. It’s not just me who puts in the work, there’s guys behind the scenes. It’s really nice when something you’ve been working for comes together."
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The Brit has endured a turbulent start to 2019, exiting the Australian Open in the first round before withdrawing from tournaments in Marseille and Rotterdam due to injury.
He was unfortunate to encounter the resurgent Tomas Berdych in Melbourne, but he conceded the defeat was a "reality check".
Edmund will make his return at the Indian Wells Challenger event next week.