Spain's Marin reaches Olympic badminton semi-finals
Marin, the 2016 women's singles champion, beat Japan's Aya Ohori 21-13, 21-14 at La Chapelle Arena to set up a final-four showdown with China's He Bingjiao.
Marin was hot favourite for the title at the Tokyo Olympics three years ago until she suffered a cruciate ligament knee tear just months before the tournament.
That kept her out for a year and came just two years after she ruptured the ligament in her other knee -- an injury that sidelined her for eight months of 2019.
Marin said it "means a lot" to be back in medal contention on the Olympic stage.
"Three years ago, I couldn't think that I would reach a semi-final here in Paris," she said.
"The journey has been a long way but I am here and I feel really proud of myself."
South Korea's world number one An Se-young also progressed with a 15-21, 21-17, 21-8 win over Japan's two-time world champion Akane Yamaguchi.
An's semi-final opponent will be Indonesia's Gregoria Mariska Tunjung, who beat Thailand's Ratchanok Intanon 25-23, 21-9.
Marin beat eighth seed Ohori in 52 minutes and looked in control of their match from the off.
"I'm proud of myself because the day before yesterday I had a difficult match," said the 31-year-old.
"Today from the beginning I wanted to keep the focus on the things that I want to improve."
China's He advanced to the semi-finals after beating defending Olympic champion Chen Yufei.
The sixth seed shocked her countrywoman with a 21-16, 21-17 win and said she felt "calm" throughout the match.
"I beat an Olympic champion today and I'm facing another one tomorrow," He said of her semi-final against Marin.
"I hope tomorrow will be a good match for both of us."