The British No 1 linked up with Belgian Fissette, who had previously worked with the likes of Kim Clijsters, Simona Halep and Victoria Azarenka, ahead of the 2017 season.
Konta said in a statement: “After careful thought and discussion, Wim Fissette and I have mutually decided to end our working relationship.
“Things ended very amicably and I wish Wim all the best. We’ve achieved a lot together and I want to thank him for all his patience, hard work and expertise.
“I will be working with my team over the coming weeks to find the right way forward for me and my tennis. The goal is to get a new coach or coaches in place as soon as possible but the focus will be on making the right decision rather than a quick decision.
“I feel very excited and optimistic about the future and very committed to improving and becoming the best tennis player that I can be.”
Konta will continue to work with hitting partner Andrew Fitzpatrick, strength and conditioning specialist Gill Myburgh, physio Milly Mirkovic and mental coach Elena Sosa.
It was a surprise when Konta split from previous coach Esteban Carril after her spectacular 2016 season, in which she reached the Australian Open semi-finals and broke into the world’s top ten.
Initially she continued her upward trend under Fissette, winning the biggest title of her career at the Miami Open in April and then reaching the semi-finals of Wimbledon to climb to fourth in the world rankings. However, her season has gone rapidly downhill since, the 26-year-old winning just two matches since her loss to Venus Williams in the last four at SW19 and losing her last five.
That miserable sequence, coupled with a remarkable run of form by France’s Caroline Garcia, led to Konta just missing out on the WTA Finals in Singapore for the second year in a row.
Konta has also been plagued by a foot injury, which forced her to pull out of last week’s Hong Kong Open and the Kremlin Cup in Moscow this week, and she has decided not to play again this season.
She could have gone to Singapore as an alternate, while she will also miss the WTA Elite Trophy in Zhuhai, a round-robin event for players immediately below the top eight.
“My foot is improving but it is still advisable to rest it further so unfortunately I will not be travelling to Singapore or to the WTA Elite Trophy in Zhuhai,” said Konta.
“Both are amazing events and I will really miss being part of them but I want to make sure I am fully fit to start preparations for what I hope will be an exciting 2018 season.”
l Heather Watson claimed a hard-fought 6-4, 6-4 victory over third seed Anett Kontaveit in the second round of the Luxembourg Open.
The British No 2 defeated the Estonian world No 35 in one hour and 23 minutes, completing the first set with a stunning forehand winner and had to survive a mini fightback from Kontaveit in the second.
A quarter-final clash against Elise Mertens awaits after the fifth-seeded Belgian saw off American Madison Brengle.