Defending champion Nia Ali failed to advance to the semi-finals of the 100m hurdles after crashing out of her heat at the world championships on Saturday.
The US team suffered a double blow at Hayward Field as Alaysha Johnson was also a non-finisher after rattling into her first hurdle in heat four of six.
There was no such drama for Puerto Rico’s Jasmine Camacho-Quinn, however, the Olympic champion sailing through in 12.52sec.
American hopes will now sit with the world silver medallist from 2019, Kendra Harrison, who set the current world record of 12.20sec back in 2016, and Alia Armstrong.
Jamaica’s Danielle Williams, bronze medallist in Doha, and her teammate, Olympic bronze medallist Megan Tapper, also qualified with ease.
“I had my speed but it just happened,” said Ali.
“This is the first time that it happened to me. It is really unfortunate that it happened here.
“Typically, where I stumble or hit the hurdle, I can recover from it. I was hoping to, but the stumble was just too deep.”
Ali said crashing out was “part of my journey and I have to embrace every part of it”.
“I am not incredibly happy about it but I have to overcome it. I wanted to do my very best in front of the home crowd. I was prepared to show a fast time, I was prepared for it.”
Camacho-Quinn said she had been content to just make it through qualification, with the semi-finals scheduled for 0010 GMT on Sunday, with the final programmed for 0200 later the same evening.
“I was not like trying to put on a super fast time, I just wanted to make it through,” the Puerto Rican said.
“So I just take the win. I am looking forward to this race to be honest… I just want to enjoy all this experience.
“It’s my first worlds, I am definitely looking forward to everything tomorrow. I was really nervous but I take what I have got today.
“Today it was just a warm-up. I will be ready tomorrow.”
After the opening two events in the men’s decathlon, Canada’s Damian Warner was in control on 2,057 points.
Olympic champion Warner, who won world bronze in Doha behind Germany’s Niklas Kaul and Estonia’s Maicel Uibo, clocked a leading 10.27sec in the 100m and went out to 7.87m in the long jump, the longest of the field.
France’s world record holder Kevin Mayer, world champion in 2017 and a two-time Olympic silver medallist, sat in sixth (1,892pts), having run 10.62sec and managed 7.54m.
Next up for the decathletes is the shot put before the high jump and 400m later Saturday.
Sunday’s competition sees the all-rounders taking on the 110m hurdles, discus throw and pole vault in the morning session before wrapping up with the javelin throw and 1500m in the evening session.
