MIAMI, March 23, 2014 (AFP) - Reigning Masters champion Scott, who led by a record seven strokes through 36 holes and by three when the day began, struggled to a final-round four-over par 76 and settled for third.
Scott, the first Australian to win the Masters green jacket, would likely have dethroned Tiger Woods atop the rankings days before he defended his first major crown next month at Augusta National.
Instead, tearful Every secured his first-ever berth at the Masters with an emotional comeback triumph by firing a final-round 70.
"It's hard. It's tough," Every said as he wiped away tears. "You never know if it's going to happen. It's nice to get it done.
"It's really cool. I've been really close. I've had a ton of looks. I still can't believe I won."
Every, whose middle name of King is the same as Palmer's nickname, won in his 93rd US PGA start, his best prior finishes being runner-up efforts in 2012 at the Texas Open and Children's Miracle network Classic.
The 30-year-old from nearby Daytona Beach, whose father brought him to Bay Hill for years in his youth, took a $1 million top prize that was more than he had earned in any prior career season.
A week that saw 14-time major champion Woods withdraw due to a back injury ended with an emotional final charge.
Every led Scott by three strokes with three holes to play but found a cart path to the right off the 16th tee and hit a tree with his second shot on the way to a bogey.
As quickly as the door opened, Scott missed a 19-foot eagle putt and pulled a four-foot comeback birdie putt left of the cup at the par-5 16th while Every rescued par from a bunker at the par-3 17th, staying two ahead of Scott.
Scott missed a seven-foot par putt at 17 and even though Every closed with a bogey by missing a five-foot par putt, Scott's par was not enough.
Keegan Bradley, Scott's playing partner, missed a 30-foot birdie putt at 18 to force a playoff and Every had his long-sought win.
"(Missing) the last putt was a bummer but I'll take it," Every said.
Scott, at Bay Hill for the first time since missing the cut in 2009, matched the course record with a 62 Thursday and equaled the 36-hole mark with a 68 Friday but saw his record seven-shot lead trimmed to three entering Sunday.
The Aussie found bunkers with his first two shots and missed a five-foot par putt at the first, dropping his lead to two shots.
Scott found water left off the third tee on his way to another bogey that trimmed his edge to one shot over Every.
Scott answered with a birdie of his own at the fourth to reach 14-under and lead by two, but he found a bunker off the tee at the par-3 eighth and took a bogey, slicing his lead back to one.
When Every sank a 20-foot birdie putt at the 10th and added an eight-foot birdie at the par-5 12th to reach 14-under, the seven-stroke edge Scott enjoyed on Saturday morning had totally vanished.
Scott, dumped from the top of the leaderboard for the first time since Thursday morning, fell two adrift when Every followed with a 13-foot birdie putt at 13 to reach 15-under.
When Scott took a bogey at the par-3 14th, missing a seven-foot par putt, Every's advantage grew to three shots and the Aussie's chance at the top spot, seemingly so near when the weekend began, faded from his grasp.
Leading scores on Sunday after the final round of the Arnold Palmer Invitational (par 72, USA unless noted):
275 - Matt Every 69-70-66-70
276 - Keegan Bradley 71-67-66-72
277 - Adam Scott (AUS) 62-68-71-76
278 - Jason Kokrak 67-71-67-73
279 - Henrik Stenson (SWE) 69-73-69-68, Erik Compton 72-68-70-69, Francesco Molinari (ITA) 67-70-69-73
280 - Brandt Snedeker 67-71-74-68, Ryo Ishikawa (JPN) 65-74-70-71
282 - Sean O'Hair 71-75-69-67, Graeme McDowell (NIR) 68-77-67-70, JB Holmes 68-69-72-73, Freddie Jacobson (SWE) 71-68-70-73
283 - Harris English 69-71-75-68, Lucas Glover 72-74-68-69, Kevin Chappell 71-70-71-71, Kevin Na 70-71-71-71, George McNeill 71-72-69-71, Matt Jones (AUS) 71-71-69-72
284 - Camillo Villegas (COL) 71-73-73-67, Brian Davis (ENG) 70-74-71-69, Gary Woodland 73-71-70-70, Vijay Singh (FIJ) 72-73-68-71, Brendan Steele 68-74-70-72, Ian Poulter (ENG) 68-71-69-76
285 - Brooks Koepka 74-70-72-69, Nicholas Thompson 71-73-71-70, Trevor Immelman (RSA) 69-72-71-73, Davis Love 70-73-69-73, Chesson Hadley 69-68-69-79