American runner Abbey D'Agostino finished the 5000m heats despite tearing her anterior cruciate knee ligament, but that injury will now rule her out of the final.
D'Agostino received plaudits during Tuesday's qualifying in Rio for helping fallen competitor Nikki Hamblin of New Zealand to her feet after the pair collided mid-race.
Although it was the American who helped the Kiwi up, D'Agostino was the worse off and needed her rival's help to complete the remaining four laps.
Although the 24-year-old from Massachusetts somehow managed to cross the line despite the nasty injury, before leaving the stadium in the wheelchair and being granted a place in the final, she will not be able to compete.
Hamblin looks set to line up for the final on Friday in Rio, while D'Agostino is content with her Olympic experience, and glad she was able to help a fellow athlete.
"Although my actions were instinctual at that moment, the only way I can and have rationalised it is that God prepared my heart to respond that way," she said.
"This whole time here he's made clear to me that my experience in Rio was going to be about more than my race performance – and as soon as Nikki got up I knew that was it.
"By far the best part of my experience of the Olympics has been the community it creates and what the Games symbolises."