After taking the first set fairly comfortably, the No.5-seeded Bouchard seemed on the verge of victory as the two kept creeping closer and closer to a second set tie-break - 2-all, 3-all, 4-all, 5-all - and Bouchard had a point to hold for 6-5. But that's when the No.3-seeded Stosur pounced, reeling off seven of the next eight points to sneak out the second set, neutralizing any immediate threat.
And after Bouchard held serve to open the third set Stosur pounced again, winning four games in a row for a 4-1 lead and never really looking back, eventually closing the match out three games later.
Stosur's biggest weapons were on display for all to see on match point - she served up a massive kick serve out wide to Bouchard's backhand, then rifled a huge forehand into the open court for a winner.
"It was a really tough match today. I'm very, very happy to win," Stosur said. "I thought Genie played very well. She had game point at 5-all in the second set and went for the drive volley and missed it wide, and then I played a very good service game to win the set - that was probably the turning point.
"It's obviously great to win, but it feels better knowing you really had to fight for it. I'm really excited about my second title here, and also the first time to win two titles in a year. It's just great."
The Australian is now an impressive 19-3 lifetime at this tournament, winning the title twice - 2009 and now 2013. She's actually the first player to conquer the International-level tournament twice.
The firsts don't stop there - this is the first time Stosur has won any tournament twice, and, having won Carlsbad in the summer, this is the first time Stosur has ever won two WTA titles in the same year.
Bouchard, the highest-ranked teenager in the world, was playing the first WTA final of her career.
"I'm disappointed because I always want to win, but I'll take the lessons from this and keep working hard," Bouchard said. "I definitely tried my best today. I feel like I was playing the right way in the first set, but she raised her level in the second set and started playing much better in the third.
"Sometimes when your opponent plays really well, you just have to congratulate them."
Stosur came back out on the court a little later for the doubles final, but she couldn't conjure up the same comeback magic - she and Zhang Shuai were beaten by No.2 seeds Kristina Mladenovic and Flavia Pennetta, 64 63. Mladenovic now has seven WTA doubles titles to her name, Pennetta 15.