World number one Nelly Korda’s lead was trimmed to three shots by a 68 from India’s Aditi Ashok with one round remaining of the women’s golf in Tokyo.

Rio silver medallist Lydia Ko is in a four-way tie for third after shooting a fine 66.

Great Britain’s Jodi Ewart Shadoff moved to one under but Mel Reid slipped back to 11 over after a 76.

Ashok, ranked 200th in the world, continued her surprise challenge with five birdies in total as she shook off two bogeys around the turn to move to 12-under for the tournament.

New Zealand’s former world number one Ko is one of four players two shots further back, alongside Australia’s Hannah Green, Denmark’s Emily Kristine Pedersen and Japan’s Mone Inami.

Ireland’s Stephanie Meadow moved three shots off the medal places with a 68 while defending champion Inbee Park of South Korea shot a level-par 71 to slip 12 shots off the lead.

Korda, who shot a nine-under 62 on Thursday to lead by four, remains in pole position after another sweltering day but was unable to move away from the field despite three birdies in her opening six holes.

“I’ve been actually really calm for the last three days, I haven’t really got nervous,” said Korda, who won her first major at the Women’s PGA Championship in June.

“But I didn’t have a really good back nine – I was kind of spraying it all over the place. I had some testy par putts, but made all pars and I fought really hard to stay in it.”

Saturday’s final round at Kasumigaseki Country Club will begin an hour earlier at 06:30 local time (22:30 BST) because a tropical storm is forecast to arrive in the Japanese capital.

Organisers hope the move will allow the tournament to be completed but if a full round is not possible on Saturday or Sunday, medals and final positions will be decided by the 54-hole standings.

“The forecast for tomorrow has shown slight improvement with the tropical system moving further east,” said a statement from the International Golf Federation competitions committee.