The Czech, a Wimbledon victor in 2011 and 2014, suffered severe cuts to her hand during a robbery at her home in December.
Kvitova seized control of the decider as she broke immediately then pressured the Barty serve again only for the momentum to swing again as Barty broke back to level at 2-2.
Last month Kvitova slipped away from Paris with an empty feeling after losing in the second round of the French Open, while Mladenovic became the home star of Roland Garros by ending the title defence of Garbine Muguruza. "I wish I could have more - I won't be sad if it is in a couple of weeks [at Wimbledon] but there is still a lot of work to be done", she said.
The 27-year-old not only looked untroubled by her hand this week but also looked back to her best with her explosive serve often too much for Barty yesterday as she produced 13 aces. "I wanted to play my best which I showed today and I hope I can keep doing that", she added.More news: Uber searches for new CEO, Mayer among candidates
"It's hard to say anything but I think I've been through a very difficult time in my life, and it wasn't about the tennis, but about coming back healthy and alive and moving my fingers properly and everything like that", Kvitova said.
Two-time Wimbledon victor Kvitova was stabbed in the Czech Republic in December which could have ended her career, escaping instead with hand injuries. But she remained reluctant to agree that she was now one of the players who could win Wimbledon.
She then decided to make her return to the tennis court 12 months ago at the 50k ITF tournament in Eastbourne where she managed to reach the semi-finals.
First, Mladenovic double-faulted going for 4-1 in the tiebreak and when she was serving at match point down at 5-6 Kvitova's widish-looking service return took a net cord, lurched into court and fell dead. "So this is quite a dream".More news: Blake Griffin opts out of Clippers contract
From the moment she broke serve for 3-2 and consolidated for 4-2 in the second set, it was clear Barty had a formula which had a good chance of working.
Whatever happens, Kvitova was already delighted with her progress.
That was all she could do, despite having a 4-0 lead in game 5 that could send her in front.
It was Safarova's second success against a seed this week, her victory over the ninth-seeded Australian following another in the first round against the third-seeded Slovakian, Dominika Cibulkova, when Safarova saved two match points.More news: Nabra Hassanen Memorial Catches Fire In Dupont Circle