Muguruza had the control of most of the match, leading 2-0 in the first set, snagging the second set in what felt like mere minutes, and leading 3-0 and 4-2 in the third. As Collins likes to say, she's a fighter, and she did just that on a chilly, late night inside Court Philippe-Chatrier to stick around long enough for Muguruza to take her foot off the gas.
"She was playing really well, and there was only so much I could do. I just told myself, OK, I've got to ride out the storm a little bit," Collins told press. "Just give it all I have. Just stick through the process."
From 2-4, Collins won four straight games and found herself in the fourth round in Paris for the first time.
"I think at 0-2, I went in with the mentality of trying to play a little bit more aggressive and to take some time away from her and to just step up and trust my shots," Collins said. "That's what I was telling myself, just to trust myself and to do the best I could because she was playing incredible."
It's just her third appearance, having turned pro after graduating from college in 2016. The 26-year-old lost in the first round in 2018 to Caroline Wozniacki and in the second round to Ashleigh Barty last year.
This time, the draw cards landed differently as the world No. 57 opened against qualifier Monica Niculescu and then dispatched another qualifier, Danish teenager Clara Tauson.
"I think every match I go out and play, I respect my opponents the same," Collins said. "Whether they are ranked No. 400 in the world or Top 10 in the world, I have so much respect for everybody that comes out and is going to compete at this level."
It's the right outlook to have given that 10 of the remaining 16 women in the draw are unseeded, including Collins. She's found her rhythm on the clay, and even though she didn't play a clay warm-up event, she grew up with a clay court in her neighborhood in Florida.
"I think I have shown through a lot of the matches here that I'm able to do some things that maybe people wouldn't assume that I'd be able to do," Collins said. "And I have been moving well on the clay courts, as well, so that's been helping me."
Check out Collins' episode of the TENNIS.com Podcast:
Collins had to deal with the unexpected against Muguruza: a court change. They began on Court Suzanne-Lenglen and due to rain, moved over to Court Philipp-Chatrier about 90 minutes later. It didn't play much of a factor since they had just started the match, while cameras continued to have no trouble zooming in on her new coach, Nicolas Almagro.
Almagro retired last year after reaching as high as No. 9 in 2011 and Patrick Mouratoglou helped link him up with Collins after she parted ways with Jay Gooding.
"I think this might be the first time I have worked with a coach that has been a Top-10 player," Collins said. "I think that's a really important thing because he knows what it takes to be at that level and that's something I would like to try to achieve."
She'll be up against No. 30-seeded Ons Jabeur for a place in the quarterfinals; Almagro has reached the quarterfinals of Roland Garros three times.
"I'm going to have to sit down with Nico and I'm sure he's going to have some great advice for me moving forward," Collins said. "The men's game is definitely different than the women's game, but I think he understands what I'm going through as a competitor."