Tibbits was able to maintain pressure on the leaders, who eventually saw their leads disappear.
Kevin Beavers, a Skyview High School graduate, was in a dead heat with UCLA freshman Cole Madey, and both had three strokes on the next closest golfer.
Tibbits finished fourth at the invitational last year.
Madey had the lowest score of the day on Saturday with a 4-under 68.
Tibbits’ birdie on the 13th was the first sign that he could really charge and then he continued charging as the unforgiving narrow fairways of Royal Oaks ate up his competition.
Beavers had a one-stroke lead at 4-under par heading into the 17th hole but back-to-back bogeys to close the round ended his chances.
Madey also had a chance to send it into a playoff on the 18th hole with a birdie but couldn’t convert as Tibbits watched before his mother gave him a huge hug.
“I didn’t really realize how good of a back nine it was until it was over,” Tibbits said.
Adding to the weight of the moment at Royal Oaks, Tibbits is the first player who is part of the Royal Oaks scholarship program to win the Invitational.
“I came up with the shots that I needed to when it mattered the most,” Tibbits said. “One of the biggest wins of my career.”
In 2012, then-president Doug Palin was approached by board member and current president Mark Curtis, about a scholarship program for youth golfers in the area.
After tracking down the USGA and the NCAA for approval, the program offers access to the club for golfers through their college careers.
“The idea was we would have a boy and a girl each year,” Palin said. “The big amateur tournament of the Northwest and he’s the first one of the scholarship kids that’s won it. Our idea was that we had kids that had a need, had a shot, had a drive to play serious competitive golf and were good students. It’s good to see that he’s done that.”
ROYAL OAKS INVITATIONAL
At Royal Oaks Country Club, Vancouver
Yardage: 7,017; Par: 72
Spencer Tibbits 71-73-69—213 -3
Kevin Beavers 71-71-72—214 -2
Cole Madey 73-68-73—214 -2
Nigel Lett 72-71-72—215 -1
Jesse Heinly 73-71-72—216 E
Jake O’Neal 70-74-72—216 E
Kasey Young 73-70-74—217 +1
Marc Rhoades 74-71-74—219 +3
Erik Hanson 73-70-76—219 +3
Jack Pennington 73-71-75—219 +3
Tanner Huddleston 71-73-76—220 +4
Brett Johnson 68-76-76—220 +4
Riley Elmes 71-72-79—222 +6
Scott Carver 75-69-79—223 +7
Drew Lunt 71-73-80—224 +8
Aaron Whalen 70-74-80—224 +8