Spain's Garbine Muguruza was unexpectedly eliminated, suffering a convincing 6-1 6-0 defeat by Barbora Strycova, while German world No.1 Angelique Kerber overcame Kristyna Pliskova of the Czech Republic 4-6 6-1 7-5. She stayed down for a long few moments, and received medical attention, before soldiering on.
But after five or so minutes of concern she got back to her feet to see out the game on her fourth match point.
Going on to break Ostapenko, the Briton was serving for the match, but her opponent's pressure was relentless, creating two break points for herself and defending a further two match points before Konta sealed the deal on the third.
Konta, who will be the first British top-10-ranked woman at Wimbledon since 1984, is aiming to win her first WTA grass-court title in her home town. "It's been a busy afternoon, we've played a lot of tennis and I'm looking forward to recovering the best I can".
In a tight service game, the Latvian broke with a superb forehand victor and backed the break up with a comfortable hold to put her just a game away from taking the match to a decider.
"I've been working really hard over the last couple of months and have been waiting for my results to come". It's another opportunity to play someone who is in great form, a Grand Slam champion, and that's something that I look forward to, also playing against players like that.
For the first time in the tournament's history there will be two British players in the semi-final.
What odds on a maiden Eastbourne final between two players from our shores tomorrow?