Towards the end of the first set Errani was visibly struggling - and then, shortly after calling the trainer to the court, she proceeded to drop the very lengthy 66-minute first set to Suárez Navarro, 7-5.
"I started to feel pain, like a knife below my ribs," Errani said. "Every time I was breathing it was very painful. It wasn't muscular, but I couldn't stay up. So I called the physio and she told me I had my diaphragm totally blocked. She tried to release it a bit, and then after that it was much better."
The threat didn't end there, though. Suárez Navarro continued her momentum, building a 4-2 lead in the second set; but Errani knew what she had to do and got right down to it, upping the aggression and winning nine of the next 10 games to take the second set and lead 5-1 in the third. Suárez Navarro made one last stand, winning two games to close that third set lead to 5-3, but the No.5-seeded Errani shut the door in the next game to close out the No.20-seeded Spaniard in a marathon, 57 64 63.
"It's a shame I lost, but I think it was a good match," Suárez Navarro said. "I think I played well from a tactical perspective. I approached the match very well. Things were pretty clear in my mind. But we all know there's a big difference between what you think and what actually happens out there.
"With Sara, the match is always going to be very long. She's always so physically tough. When it was 4-2 or 4-3 in the second set, I dropped my intensity a bit but she upped hers. So all the credit to her."
Suárez Navarro was still pleased with her overall tournament, though. "It's obvious that once you get to the round of 16, it gets harder and harder," she said. "My goal was to make it far in this tournament and I did, and Sara is so tough, so I have to be happy with how I did this tournament even if I lost.
"Now it's time to prepare for the grass. I like grass a lot, and when I've played on grass I've had pretty good matches. So I'm really looking forward to playing all of the upcoming tournaments."
But back across the water, there's the second week of Roland Garros going on - and Suárez Navarro was asked in her post-match press conference who she considers the favorite to go all the way.
"This tournament has proven very interesting," she said. "On the first day I was asked this, in fact. I was asked whether I saw Serena as a favorite. I told them she is a great player, but I think Kuznetsova is going to be very tough. I also think Errani will win against Radwanska or Ivanovic in the quarterfinals. Sara won't be happy enough with the quarterfinals, she will want to go further. On the other side we've got Sharapova and Azarenka as well. There are a lot of players who can win the tournament."
Errani's 35 wins on the season is second only to Serena Williams, who scored her 40th on Sunday.