In a match where the outcome was in the balance until the very end, Wozniacki drew on all her reserves of physical and mental energy to triumph, 7-6(4), 6-7(5), 6-2.
From the outset, Wozniacki’s counterpunching game was at its brilliant best, frustrating Sharapova for the duration of a see-saw encounter with her endless retrieving.
While Sharapova's competitive fire burned as fiercely as ever, she was undone by service woes, aiding her opponent's cause with 15 double faults.
A couple of these helped Wozniacki edge ahead in the final set, before she finally closed out the match after three hours and 13 minutes.
"I'm feeling a little tired! But it was a great match and great to make a winning start," Wozniacki said. "It's always tough to play your first match and get into rhythm on a new court.
"I’m just so happy to win and the crowd was unbelievable out there."
It was a memorable return to the fold for Wozniacki, whose last WTA Finals appearance came in 2011. A brilliant sequence of results over the summer, crowned by a run to the US Open final, laid the foundations for qualification, and she is enjoying life back amongst the elite.
"Everyone wants to be here. At the start of the year it’s our goal," she added. "In the middle of the year it didn’t look like I had a chance but I had an amazing summer, reached the US Open and now I’m back. It feels great!"
Having pinched the opening set thanks to a run of five straight points in the tie-break, Wozniacki looked to be on course for a straight set win when she broke late in the second.
However, Sharapova promptly summoned her best tennis of the match, a brilliantly disguised drop shot helping her to get back on level terms before taking another dramatic tie-break. The Russian was unable to build on this breakthrough, dropping serve immediately at the start of the decider.
While this deficit was soon wiped out, Wozniacki's tireless running continued to pay dividends. The Dane capitalized on a double fault and a couple of wild groundstrokes to move 4-2 ahead, before repeating the trick a few moments later to get her campaign off to the perfect start.