The British number one beat Barty in the quarter-finals at Nottingham previous year.
Barty is 1-1 in finals this year after falling in the Sydney championship match.
Barty, who dropped just two service games in the tournament so far, lost nine points on serve during the match and perfectly used her sliced backhand to maintain the edge over the rising Japanese star, the only semifinalist who has never played a grass-court final (Donna Vekic has played two and Ashleigh Barty and Johanna Konta one each). Do you fully understand that?' "Obviously I'm a little bit sad I could not come through with the win today but I'm also taking a lot of positives from this week in general". It has been a hard season for a player who was ranked fourth after reaching the semi-finals of Wimbledon last summer and is now down at 22.
The Brit then stormed off court, with organisers rushing to get her back for the trophy presentation.
Elsewhere, second-seed Australian teenager Alex de Minaur eased past Belarusian fourth seed Ilya Ivashka, 6-2, 6-4, in the ATP Challenger event to set up a Sunday showdown with Briton Evans.More news: LeBron James Will Likely End Up In One of These Cities
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"We've had some incredible battles, especially the last two times", said Konta. She responded to the umpire by saying: "I am a human being, no a robot".
"Those two had two cracking matches on the grass a year ago". The Scot had several aborted comebacks, having limped out of Wimbledon last July before going under the knife in January. It was just about, from my end, dealing with it the best I can and keep the attention on the work at hand.
"I lost to Jo here past year, so I think I can go in and play some pretty free tennis".
"I really hope to see him back playing at that level he has played over the last couple of years".
The Croat is playing her 20th overall semifinal and is now 17-3.