A day after pulling off a Houdini-like escape against No.2 seed Ana Ivanovic in the semifinals - she was down a set, and 3-0 down in the third set - the No.1-seeded Halep scored another come-from-behind victory against No.4 seed Stosur in the final, looking completely out of it in a 31-minute first set but rebounding very nicely in the next two sets to beat the Australian to the season-ending title, 26 62 62.
Halep won 20 of the last 26 points of the match, finishing it off on a forehand down the line winner.
"I really wanted to win this tournament, so I'm just happy!" Halep said in her on-court interview after the match. "It has been a great tournament for me. And well done to you Sam, you played well all week."
Throughout the week Halep was urged on by crowds of supporters from neighboring Romania - and they were among the many people the Romanian No.1, who will now be No.11 in the world, thanked.
"I want to thank everyone who came to support me this week, they helped me a lot," she said. "I also want to thank my team, my friends and my family, and of course Ilie Nastase who came to support me!"
Nastase, a fellow Romanian who was the ATP World Tour's first World No.1 back in the early 1970s, was also interviewed after the final. "This is my first time here after 51 years - I was 16 the last time I came here!" he said. "To finish the year with a win like this is great for Simona. It will give her confidence going into the new year, which begins pretty soon in Australia. Congratulations to her."
As for Halep, as recently as May she was just another young player trying to break through - a former junior No.1, a three-time finalist on the WTA. Now, less than half a year later, she has six WTA titles - Nürnberg, 's-Hertogenbosch, Budapest, New Haven, Moscow and now Sofia - and she is on the verge of becoming the third Romanian ever to break the Top 10 on the WTA (after Ruzici and Irina Spirlea).
What's next for the 22-year-old? "I want to enjoy this moment and then take some holidays, and just relax," she said. "Hopefully I can play next year like I played this year and do well in Australia."
Though she didn't come away with the title, Stosur has a lot to be happy about. After nearly falling out of the Top 20 a month ago - she actually fell to exactly No.20 in the world for two weeks - the former World No.4 has rebounded nicely, winning 12 of her last 15 matches, a stretch that includes winning the Osaka title and reaching finals at Moscow and now Sofia (falling to Halep both times).
"Congrats to Simona on playing a great final," Stosur said. "She's a very good player - she got me a couple weeks ago in Moscow, and again it was very hard today - but I'm happy with the week I had.
"Now I'll take a break and then think about next season in a few weeks when I start training again."