(CNN) A minor adjustment from Serena Williams that had nothing to do with her racket or footwork made all the difference, she noted, in her gripping victory in the Wimbledon quarterfinals.
Locked in battle with fellow American Alison Riske on a blustery day in southwest London, Williams took action in the tense decider when her hair was "getting in the way."
"I was missing a shot because it's in my face," Williams told reporters. "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."
And she did.
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Williams cranked up her level at crunch time in a scene regularly played out over her three-decade career. And she saved her best for last, striking more aces, winners and tallying her tidiest winners-to-unforced errors ratio in the third set against the conqueror of world No. 1 Ashleigh Barty to reach a 12th Wimbledon semifinal.
Awaiting the 37-year-old Thursday as she continues her quest for a 24th major is Barbora Strycova, a grass court-loving 33-year-old, who became the oldest first-time women's grand slam semifinalist in the Open Era in what could be her farewell appearance at Wimbledon.
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Strycova -- the most experienced of seven Czechs in the top 100 -- hasn't ruled out retiring come the end of 2019.
The other semifinal pits former London resident Elina Svitolina -- her own semifinal drought at grand slams is now a thing of the past -- against Simona Halep in a battle of speedy baseliners who seem to have overcome their grass-court foibles.
Williams, by contrast, has won Wimbledon seven times, and if she can maintain Tuesday's stellar form, number eight figures to be on the way.
According to Riske's coach, it was one of the finest performances from Williams on her comeback after becoming a mom in September 2017.
"I watched a lot of tape before this match, I watched a lot of Serena kind of in the last couple of years to see what she has been like," Billy Heiser told CNN, adding he didn't go further back because Williams was "basically unbelievable."
"Honestly, I felt this was the best match she's played in quite some time. Definitely all year. And I thought Ali brought that out of her and made her play and dig really deep.
"Serena should have all the confidence in the world. She played a two-hour match that was physical and she responded with some of her best stuff in the end."
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Williams' coach Patrick Mouratoglou agreed.
"That was a high-level match," he told CNN.
Williams later went out and bossed her mixed doubles match with partner Andy Murray, ripping returns against towering Frenchman Fabrice Martin and chasing what appeared to be lost causes with success.
The duo, dubbed "Murr-ena" or "Ser-Andy," lost to top seeds Nicole Melichar and Bruno Soares Wednesday, but just deciding to play mixed doubles was encouraging from Williams, an indication that her left knee can handle the extra workload.
"This is the first time since Australia that I actually felt, like, good," said Williams. "It's been a really, really long year for me already, and hard year, because I'm usually not typically injured.
"Now that I feel good, I can actually focus on training and technique and practice, something I just literally haven't been able to do a lot of."
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Australia was the site of Williams' previous clash with the 54th-ranked Strycova in 2017.
She won in the fourth round and proceeded to land a 23rd major while pregnant with daughter Olympia, but not before the 5-foot-5-inch Strycova -- who topped Maria Sharapova in the 2002 Australian Open junior final -- led by a break 4-3 in the first set.
The nine games Williams conceded overall were the most she lost in any match that fortnight.
"I don't have fear," Strycova told reporters. "I just will go there Thursday and I will try to play my game. Of course, I don't have such power like Serena, but I have other weapons. I will try to use them as much as I can. I will enjoy. I have really at this point nothing to lose."
Strycova and her varied game crushed the hopes of British fans, eliminating Jo Konta 7-6 (7-5) 6-1 after trailing 4-1 in the first. She served and volleyed, sliced forehand returns to repel Konta's potent first serve and hit deft drop shots.
Strycova found herself in even more dire circumstances Monday, behind by a set and 5-2 before rallying against Elise Mertens.
Like Williams she is competing in doubles -- women's doubles -- one of the favorites alongside magician Hsieh Su-wei.
Though never a champion at Wimbledon, she got a close up view of the Venus Rosewater Dish -- presented to the ladies' winner -- when much, much younger.
"I was two years old when my grandpa took me to the (Wimbledon) museum," she said. "I saw the trophy. I was like, 'I'm going to play here.' Right now, here I'm 33, which is incredible. It's a great story."
One that would escalate, and substantially, if she defeats Williams at the business end of Wimbledon.