Johanna Konta battled back from from the brink to win a three-set thriller against Simona Halep and become Britain's first women's singles semi-finalist at Wimbledon since 1978.
It is 39 years since Virginia Wade reached the last four at the All England Club and Konta now stands just two wins away from matching Wade's more notable feat of a year earlier, when she was crowned the Wimbledon champion.
Konta trailed by a set on Centre Court and was two points from defeat in the second but she refused to lie down and instead surged back to win 6-7 (2/7) 7-6 (7/5) 6-4.
The British number one will face Venus Williams on Thursday, who beat French Open champion Jelena Ostapenko, for a place in Saturday's championship match.
It could have been Halep, not Ostapenko, playing here as the queen of Roland Garros were it not for a meltdown in last month's final but the 25-year-old could hardly be accused of throwing this one away.
Konta won it, through her brave baseline hitting and relentless attitude which have now seen her emerge from three final sets in five matches, each one the victor.
Defeat ended Halep's hope of taking the world number one ranking, which instead will transfer from Angelique Kerber to Karolina Pliskova next week.
"Right now it's a little bit surreal," Konta told the BBC.
"I stuck to my true self and tried to create as many opportunities as possible. I knew she was not going to give much away for free so I definitely had to be the one to create my own chances. I did that and feel fortunate to have taken a few of them."
On facing the 37-year-old Williams, a five-time Wimbledon champion, Konta said: "Age is not a factor. She's a tremendous champion and I feel very humbled to share a court with her again."
After two hours and 38 minutes, a pulsating match ended on an awkward note as Halep patted a forehand into the net, having been prompted to stop by a scream in the crowd.
But, after two days of the game's biggest names questioning this tournament's preference for men's matches on its show courts, here was otherwise a dazzling advert for women's tennis, played at a ferocious pace by two players at their technical and physical best.
Halep had accused Konta of gamesmanship during an acrimonious Fed Cup tie in April and there was, briefly, a sniff of lingering animosity when the Romanian questioned how long her opponent took for a toilet break at the start of the decider.
Konta should also have benefited from the closed Centre Court roof, which sped up the pace, not to mention the cheers of a raucous home crowd.
The Briton was up at the net from the very first point, following in a hammering forehand return, but where previous opponents might been overawed, Halep curled a forehand pass coolly into the corner.
It set the tone early on as Halep stormed into a 4-1 lead but Konta broke back with a sizzling backhand winner.
Halep, in the face of momentum, the crowd and Konta's unwavering first serve, never flinched, instead holding on for the tie-break when her class really told.
In the point of the match, she chased down a Konta drop-volley before flicking it diagonally onto the line. Konta shanked a drive volley long and Halep walked in one set to the good.
There was nothing between them at the start of the second set but Konta spurned a chance at 4-3. With two break points, she slapped one return into the net and flashed another long.
It would be settled in another tie-break as a Halep forehand landed bang on the line for 3-1 but Konta battled back to 3-3. Four points later, it was still neck-and-neck but two strikes from Konta into the corner and this time she snatched the set.
Konta strode off court for a six-minute toilet break, leaving Halep to stew in her chair. After five minutes Halep asked umpire Kader Nouni how long her opponent was allowed before pointedly rolling forehands into an empty court.
It was hard to say it affected Halep as she was first to have a break point at 1-1 but Konta saved it and then broke serve, a pump of the first sealing the 3-2 lead.
Halep looked weary, of her opponent and the crowd, but she gave nothing more away and made Konta serve out at 5-4.
A dipping cross-court backhand gave Konta 30-15 and then she read a Halep forehand to open up two match points. Halep hit deep and a spectator, presumably thinking it was out, screeched. Halep plopped a forehand into the net but after a moment's confusion, there was no question who was the winner.