Pennetta had won all three of the pair's previous meetings but looked completely down and out in this one, dropping the first set in just 20 minutes and losing the first game of the second set to fall behind 60 10. She caught fire from there, winning five games in a row to build a 5-1 lead, but Cornet caught back up, winning the next five games and eventually building a 3-0 lead in the second set breaker.
That's when the former Top 10 player in Pennetta came alive again, hitting crisply and aggressively to win seven of the next eight points and sneak out the set, and rolling through the third as well.
"I think I started really tight in the beginning of the match. I wasn't pushing her at all, like I didn't hit a good ball from the beginning," Pennetta said. "After the first set I just tried to hit the ball more and more, I started getting more power and my serve started working a little better as well. I really felt in the second set I was really enjoying it a little bit more and playing my tennis. And the tie-break was crazy.
"I have to say I'm really happy about this match today."
It has been a rough go of things over the last year for Pennetta. A former World No.10 who was ranked in the Top 20 early last year, she suffered a right wrist injury last April and by August it was too much to bear - she withdrew from all tournaments for the next six months, including Grand Slams at the US Open and Australian Open, underwent surgery in the fall and returned to action this February.
So, reaching the fourth round this fortnight is a welcome return to the top tier for Pennetta.
Up next for the Italian is No.20 seed Kirsten Flipkens, who hit 29 winners to just 14 unforced errors en route to a 64 62 victory over Vesna Dolonc. It's the second time Flipkens has made it through to the second week of a Grand Slam - she did it in Australia this year before falling to Maria Sharapova.
Flipkens was asked about how all the top players on her half of the draw going out affected her.
"Actually, I am not somebody who likes to look forward," Flipkens said. "Okay, it's clear that Serena is the favorite. She was already the favorite before. It's clear that she's now the one to beat in this tournament. But I think she will still just stay focused on every match she's playing here. I don't think she's going to be looking forward too much and thinking about all of the seeds who are out.
"And I'm focusing match by match. I'm not even looking at the draw because I don't like to see what could happen. If you look at the draw and the possible quarterfinals, it doesn't make sense anymore - especially not on grass, especially not in this tournament with all the retirements and withdrawals.
"I'm just going match by match. That's the way I want to do it and that's the way I'll do it."
Flipkens and Pennetta are tied in their head-to-head series, 1-1, with Pennetta winning at the French Open way back in 2006 but Flipkens winning at the same venue - the French Open - just last month.
"In Paris I lost, but I would like to win this time," Pennetta said. "I think she plays really well on grass, so it's going to be a tough match. I'd just like to play my game. In the first set today I felt so bad because I wasn't doing anything with the ball - nothing at all - it was not my game at all. So I would just like to play my game, enjoy the match, and we will see what happens when we play each other."
"It's a nice experience for me to be here for the first time in the fourth round," Flipkens said. "I am really looking forward to having a good match, especially against Flavia. She's had a lot of injuries in the past, and she's such a nice girl, so it's good to see her playing so well at Wimbledon this week.
"We just played each other in the French Open, but everybody knows clay courts and grass courts are like black and white, so I'll for sure have to prepare and be as ready as I can for the match."
The Belgian was asked which she prefers - black or white. "I prefer white," she said.