The British number one, 28, meets Czech teenager Marketa Vondrousova in a last-four match pushed back to Friday by bad weather on Wednesday in Paris.

No British woman has reached the Roland Garros final since Barker won her only Grand Slam in Paris 43 years ago.

"Jo is playing the best tennis I have ever seen her play," Barker said.

American great Billie Jean King agreed with Barker, saying Konta was now a better player than she was when she reached the 2017 Wimbledon semi-finals.

Konta, seeded 26th, has only dropped one set in her march to the semi-finals and produced a stunning performance to beat American seventh seed Sloane Stephens in Tuesday's quarter-final.

Konta will compete in her third Grand Slam semi-final - on a third different surface - after also losing in the 2016 Australian Open last four.

She had never won a main-draw match at Roland Garros until this year.

"It is her mental approach to matches. She used to have a wobble in matches and sometimes let the other player back in, but she just hasn't had that in any match," said Barker, a former world number three.

"She dropped one set but even in that match she looked really good.

"I am really impressed that she is playing that well for the whole match. Her confidence must be sky high, hitting the ball that well and feeling it so well.

"She can go all the way here, I think she is playing the best tennis of anybody."

Rain washed out Wednesday's play in Paris, meaning the two remaining women's quarter-finals will take place on Thursday.

Romania's defending champion Simona Halep will play American 17-year-old Amanda Anisimova, with Australian eighth seed Ashleigh Barty facing American 14th seed Madison Keys.

Konta's semi-final was pushed back to Friday to ensure both last-four matches are played on the same day.

King, a 12-time Grand Slam singles champion, says any of the women left in the draw are capable of lifting the Coupe Suzanne Lenglen following Saturday's final.

"I don't know if we have a favourite. I really do think it's wide open," said King, who has been announced as the ambassador for the revamped Fed Cup.

"Konta is in the best position she's ever been because she's had more experience, she's won more.

"She's really concentrating well and she's hitting so big. Her serve's big, her groundstrokes are big.

"She's totally focused right now - she just needs to stay the way she is. But she's going to have to think because of the creativity of Vondrousova."