Dafne Schippers won the headline race at the IAAF World Championships on Friday to retain her women's 200 metres crown.
The sprinter is one of the stars of women's athletics, but the 3000m steeplechase may have produced two more after a pair of Americans caused an upset.
Jamaica's struggles continued with the elimination of Danielle Williams from the women's 100m hurdles, while Caster Semenya's progression to the 800m final was never in doubt.
It was also the opening day of the decathlon, with France's Kevin Mayer heading into the second half of the event with a 57-point lead over Kai Kazmirek of Germany.
Here we take a look at the biggest stories from the evening session at London Stadium.
SCHIP SCHIP HOORAY
Schippers, who claimed bronze over 100m earlier this week, had to battle hard in the closing stages of the 200m to hold off the challenge of Marie-Josee Ta Lou.
Schippers ran 22.05 seconds to edge Ta Lou by three hundredths - a second agonising defeat for the Ivorian after she finished the 100m final one hundredth behind new champion Tori Bowie.
Shaunae Miller-Uibo went some way to atoning for her 400m collapse by clinching bronze, marking her first medal at a global competition over the shorter distance.
"It was very important to win," said Schippers. "I worked so hard in the last years and last year was not the easiest for me. I changed everything and got a new coach, so I'm very happy.
"It's great, especially with a gold medal, I am very pleased. My secret is enjoying the sport and enjoying my racing. I feel a little bit nervous starting out, but I'm a final runner and I'm grateful for the experience now it's over."
AMERICAN ONE-TWO BREAKS AFRICAN STEEPLECHASE STRANGLEHOLD
Ever since Habiba Ghribi won women's 3000m steeplechase gold for Tunisia at the 2011 World Championships in Daegu, every major international title has been won by an African-born athlete.
But US duo Emma Coburn and Courtney Frerichs broke that dominance in emphatic fashion on Friday, coming home in first and second respectively with Coburn setting the first championship record of the week in London.
"Oh my goodness, what a race to be part of," said Coburn. "I have memories from 2015 and 2016 where I went too early for the last push, so I just had to keep trusting myself and be patient, and it looks like it paid off.
"I never expected to win in that time but I kept pressing. It is pretty amazing to get a championship record."
There was embarrassment for Kenya's Beatrice Chepkoech when she forgot about the water jump on one lap, although after running back to correct her error she managed to finish a creditable fourth.
It was another good session overall for the US, as they also claimed gold in the women's long jump, with Brittney Reese repeating her success of London 2012 ahead of neutral athlete Darya Klishina and Olympic champion Tianna Bartoletta.
JAMAICAN WOE CONTINUES IN WOMEN'S SPRINT HURDLES
It has not been a stellar year for Jamaica so far. Usain Bolt's failure to cap his glittering career with one more individual gold is just the tip of the iceberg when it comes to the country's underperformance in London.
And there was more disappointment in the women's 100m hurdles, as defending champion Williams exited the competition in the semi-finals thanks to a scrappy race in which she clipped several hurdles.
World record holder Kendra Harrison also hit a hurdle early on but recovered to qualify as a fastest loser, while 2012 Olympic champion Sally Pearson looked close to her best back at the scene of her greatest triumph.
"I haven't come here to come second," she said. "I'm just happy to be going through the rounds and feeling good; it's a matter of doing it to my own art.
"It would have been great to be back running at a World Championships anywhere in the world, but I guess it's a bonus and super special to be back in London."
SEMENYA SAILS THROUGH
Already a bronze medallist in the 1500m, Caster Semenya is looking strong over her favoured distance of 800m.
The Olympic champion came out on top in her semi-final with a time of one minute and 58.90 seconds - the quickest across the three races.
"We are just trying to enjoy what we do and I tried to calculate how to run the race," she said. "I just needed to keep my muscles moving. Anyone can win the race."
The two women who joined Semenya on the podium in Rio de Janeiro last year - Francine Niyonsaba and Margaret Wambui - both came through the slowest of the three semis as the top two.
The only other gold of the session went to Pawel Fajdek of Poland in the men's hammer, the 28-year-old retaining his title for a third-successive championships with a throw of 79.81 metres.