If it was the last time Lee Kiefer took the competitive piste, it’s hard to imagine a better way to go out. The 30-year-old medical student from Lexington, Kentucky, wrote herself into fencing history on Sunday night, roaring to a second straight Olympic gold medal in the women’s individual foil with a dazzling 15-6 win over younger teammate Lauren Scruggs in a rare all-American final.

Scruggs, the precocious 21-year-old Queens native and rising Harvard senior, made history of her own in defeat, becoming the first Black American fencer to win an individual medal in a women’s event. But the Olympic debutante proved no match for a defending champion driven by a self-belief that comes only with experience.

Operating with the urgency of someone with a taxi waiting outside, Kiefer conjured a masterclass of speed, precision, timing, in-fighting and mental fortitude with the sport’s ultimate prize on the line. Quicker in every exchange, she rattled off six straight touches from 1-2 down, then seven of the last eight to close the show with 40 seconds to spare in the opening period. It was the performance of a lifetime.

Related: Torri Huske roars back to edge Walsh for gold in US 100m butterfly one-two

“No matter how much I tried to prepare, there’s still so much pressure I put on myself to just fence well and stay present,” a jubilant Kiefer said afterward. “Each day was a rollercoaster, but here we are at the top.”

In the end it was Kiefer’s greatest asset, her blinding speed, that left Scruggs chasing phantoms for the brief time as it lasted. The four-time Olympian, whose agility and balletic footwork make up for any disadvantages posed by her slight 5ft 4in frame, effortlessly picked her foe apart with a mature repertoire of attacks, parry-ripostes and stop-hits, the outcome rapidly growing beyond negotiation as the avalanche gathered pace.

After the decisive touch Kiefer tore off her mask and leapt in celebration beneath the majestic barrel-vaulted glass roof of the glamorous Grand Palais, which amplified the roars of the rowdy crowd of 6,100 spectators to ear-splitting volumes. She embraced Scruggs at the center line before coming together with Amgad Khazbak, the longtime coach who spotted her talent nearly two decades ago at the Bluegrass Fencers’ Club in Lexington. The two strode back and forth along the strip raising an American flag while a misty-eyed Kiefer blew kisses to a teeming family section that included Gerek Meinhardt, her husband of five years and the other half of fencing’s power couple, a two-time bronze medalist in men’s team foil who will look to add more to the family haul on Monday in the men’s individual foil competition.

Three years ago Kiefer became just the second American woman ever to win individual Olympic fencing gold when she defeated the defending women’s foil champion Inna Deriglazova in the gold medal bout in a near-empty convention center on the outskirts of Tokyo. That marked only the third gold in US history in fencing, which is one of only four sports to have been on the programme at every modern Olympic Games dating back to 1896.

Now Kiefer has taken her place among the rarified air of back-to-back Olympic champions, joining Mariel Zagunis of the US (sabre), Italy’s Valentina Vezzali (foil) and Hungary’s Timea Nagy (epee) among recent women to defend an individual title. Besides Vezzali, the only other woman to win consecutive golds in individual foil was Hungary’s Ilona Elek-Schacherer, who did it in 1936 and 1948.

“My first gold, I was not expecting myself to be able to compete like that with the Russians and the Italians,” said Kiefer, who was born in Cleveland before her family relocated to Lexington when she was young. “So it’s a pleasant surprise. I think I’ve grown my skills over the past few years and it becomes just a mental game every day trying to stay positive, trying to keep working at the details. There’s a lot of pressure that I placed on myself, so it was hard, but all the more beautiful because of that.”

Kiefer’s historic title defense is only the latest high achievement in a life defined by mountains climbed and obstacles denied. A four-time National Collegiate Athletic Association (NCAA) champion at the University of Notre Dame, the Filipino-American didn’t strike gold until her third Olympic trip after placing fifth at London 2012 and 10th at Rio 2016.

Since enrolling at the University of Kentucky College of Medicine alongside Meinhardt, the self-described “pretty shy, reserved person” has become a staunch advocate of reproductive justice. She volunteers as a helpline operator with the Kentucky Health Justice Network, a non-profit that provides funding and education for Kentuckians seeking abortion care. Her commitment to the cause only redoubled in 2022, when the US supreme court overturned Roe v Wade.

Related: Simone Biles returns to Olympics as the circus screams on around her

Having taken leave from medical school along with Meinhardt to train for their fourth Olympics, Kiefer has said that she plans on returning to her coursework next year. But after Sunday’s breathtaking display on the sport’s biggest stage, the prospect of going for a third straight gold on home soil at the 2028 Los Angeles Games surely must be tempting.

“I’m trying to think about Gerek’s event tomorrow and our team event and a men’s foil team event” Kiefer said. “That’s as far as we’re getting into the future for now.”

If it was indeed the end of Kiefer’s sporting career, the future of American fencing appears in good hands with Scruggs, the ninth seed who sprung the upset of the tournament over Italian favorite Arianna Errigo in the quarter-finals, then was reduced to joyful tears after winning her semi-final 15-9 over Canada’s Eleanor Harvey to ensure at least a silver. Simply reaching an Olympic final capped an extraordinary rise for the native New Yorker, who finished 25th in her first and only world championships a year ago this week.

“I’m from New York City and I just feel like you have to be super-confident just in how you go about life there,” said Scruggs, who trained at the Peter Westbrook Foundation, a non-profit renowned for introducing fencing to inner-city youth. “I think I kind of brought some of that with me today.”

She added: “Fencing has largely historically been a non-Black sport, so I hope to inspire young Black girls to get into fencing and to think that they can have a place in the sport. I just hope that more people who look like me, more little girls like me, feel they have a place in the sport.”

Kiefer, seeded second but up to No 1 in this month’s world rankings, had sailed through the preliminary rounds earlier Sunday but had a harder time in her semi-final with Italy’s Alice Volpi in a showdown of two of the finest fencers of their generation. But while Volpi entered with a 67% win percentage over Kiefer, including once at a world championships and both of their two most recent meetings, the American held her nerve to book a place in the final.

Both Kiefer and Scruggs will have a chance to add to their Paris medal count on Thursday in the team foil event, where the United States are seeded fourth of eight entries.

Harvey, a three-time Olympian from Ontario, made it a North American sweep by winning 15-12 in the bronze medal contest over Volpi, the defending world champion who cut a hard-luck figure after settling for fourth at a second straight Olympics. It was Canada’s first ever medal in fencing.