"I'm very excited and shaky and all that good stuff," Sinclair said after receiving the news.
Sinclair, who said she is an avid visitor to AVN's websites, said she contemplated for several days before entering the contest.
"Finally, my husband said, ‘Would you just submit your picture already!'" she said.
Sinclair earned a 7.7 rating after all 16,106 votes were cast.
"I'm so excited about the many participants in AVN's very first holiday contest," said MaryBeth Barnett, director of digital media for AVN. "We had super-sexy entries from all over the world, and voters had fun choosing their favorites."
The hot-or-not-style photo competition was conducted at AVNContest.com from Dec. 3-20.
There were 62 entries, including five men. Coming in at a close second was Vanilla DeVille, who drew a 7.5 rating. The third-place finisher was Tyler Stevens, who had a 7.3 rating.
Notable entries included Halcyon from FlashCash.com, Curious Toy Boy of LionDollars.com and Howard Levine of Club Jenna.
For winning, Sinclair will receive two tickets to January's AVN Adult Entertainment Expo and two tickets to the 25th Annual AVN Awards show in Las Vegas.
"You know, this was going to be the first year in a while that I wasn't going to make the trip to Vegas," Sinclair said. "I guess AVN didn't want me to miss it!"
Another big winner in the "Santa Baby" contest was voter William Brook, who was randomly chosen to receive a Santa swag bag valued at more than $200. The bag includes an Adult Toy Box from For Your Nymphomation, a stainless-steel njoy pure wand from njoy toys, a Do Not Disturb kit from Sportsheets, Raspberry Vanilla Body Dust from Good Vibrations and H2O Water-Based Lubricant from Sliquid.
With the success of the "Santa Baby Contest," AVN plans more fun in the coming months.
"Stay tuned for details to our Valentine's Day contest!" Barnett said.
The contest was sponsored by ImLive.com.