Serena Williams overcame fellow American Alison Riske to reach the Wimbledon semi-finals as she closes in on an eighth All England Club title and a 24th major overall.
Riske, unseeded and ranked 55 in the world, upset top-ranked Ashleigh Barty in the fourth round and was playing in her first major quarter-final in her 30th appearance at a Grand Slam tournament.
She was not overawed by the presence of former world No 1 Williams - converting every single break point she created.
But it was 37-year-old Williams who eventually prevailed in a in a thrilling three-setter, winning 6-4 4-6 6-3 to reach her 12th semi-final in 19 appearances at the Championships.
"I just needed to just fight," admitted Williams. "Alison, I mean, she played great throughout the whole tournament. She's beaten so many amazing players, players that have had great years.
"She was not giving it to me. I needed to step up and take it. That's what I had to do."
Having been pegged back by the stubborn Riske, Williams seemed to find a second wind after tying her hair up.
"It was just in my way. I was missing a shot because it was in my face," she said.
"I was like, 'this is not happening'. I just needed to get it out of the way, put the business bun up and just get to business."
Williams was down a break twice in the opening set but came back both times and broke again in the final game. Neither player was serving badly, but both were returning superbly.
The second set rumbled on with serve until 4-4 when Riske conjured up a powerful return which smacked the baseline followed by a delicate volley, before holding to love and levelling the match.
Breaks were exchanged again twice at the start of the decider, the Americans now matching each other blow for blow until a stunning Williams volley and a Riske double-fault broke the 29-year-old once more.
Serving for the match after two hours and one minute, Williams fired down an 18th ace to pass her toughest test yet and reach the last four.
Halep sets up Svitolina clash
The highest seeded woman left in the draw Simona Halep made it through to her second Wimbledon semi-final with a straight-sets win over Zhang Shuai.
After beating teenage sensation Coco Gauff in straight sets, the seventh seeded Romanian found herself 4-1 down in the opening set as China's Zhang briefly threatened a shock.
But Halep recovered to take the first set on a tie-break and then raced through the second to win 7-6 (7-4) 6-1.
In her first semi-final appearance at Wimbledon since 2014, Halep will meet either eighth seed Elina Svitolina for a place in Saturday's final.
Svitolina came from a break down in both sets to beat Karolina Muchova 7-5 6-4 and reach her first Grand Slam semi-final.