Johanna Konta has split with her coach Michael Joyce after less than a year together.
The British No 1 will now begin the search for a new coach – her fourth in three years – in time for the new season.
In 2016 Konta split with Esteban Carril and at the end of last season her association with Wim Fissette also came to an end.
Konta’s ranking has slipped this season – she is now down to 45 having been as high as four in the world following her run to the semi-finals of Wimbledon last year.
It has been a tough season, at least in the grand slam events, with first-round losses at the US and French Opens and second-round exits at Wimbledon and the Australian Open.
The 27-year-old did, however, hand Serena Williams the biggest defeat of her career, 6-1 6-0, at the Silicon Valley Classic in San Jose in August.
American Joyce, 45, had previously been Maria Sharapova’s coach for seven years.
British men’s No 1 Kyle Edmund is through to the last 16 of the Shanghai Masters after victory against Andreas Seppi.
The 23-year-old, who reached the China Open semi-finals last week, continued his good form with a 6-3, 6-4 success over the experienced Italian to set up a tie against world No 48 Nicolas Jarry of Chile.
Defending champion Roger Federer had to overcome a second-set stutter before overcoming Daniil Medvedev 6-4, 4-6, 6-4.
Juan Martin del Potro displayed his battling qualities to overcome Richard Gasquet. The No 3 seed fought back on two occasions, winning four straight games from 3-5 down in the first set and then recovering from a 2-6 deficit in the second set tie-break to win 7-5, 7-6 (9/7).