Geoff Gonzalez never led until the 27th hole, but once he grabbed the lead with a birdie, he never let go.

The senior-to-be Cal Poly golfer defeated Jeff Wilson of Fairfield 3 and 2 in the championship final of the 98th California State Amateur on Saturday at the Lake Merced Golf Course.

Gonzalez won four holes during a seven-hole stretch midway through the final 18 holes of play, thus becoming the first player in 15 years and only the 12th overall to win the championship and medalist honors.

Wilson, 46, was seeking to enhance an already glittering resume. The all-Northern California final, the first since 2004 when Spencer Levin won, was initially a Wilson show, as the Green Valley CC member took a 3-up lead into the eighth hole of the 36-hole final. But the 21-year-old Gonzalez was able to square the final by the end of the morning 18 through gritty putting.

“Once I started making putts I built off that confidence,” the champion said. “It was big to square the match at the end of the first 18. “

Gonzalez took his first lead on the 516-yard ninth hole, the 27th hole of the championship final, with a birdie four and also won the par-3 12th hole and par-5 14th to build his 3 and 2 conclusion, again on the strength of solid putting.

“I was down in every match I played,” the Diablo resident said. “I was used to coming from behind.”

The rising senior at Cal Poly and 2006 Monte Vista (Danville) High School graduate entered the California State Amateur for the first time in 2009, and marked the culminating point in a several-month process of game improvement. Before a few months ago, Gonzalez had not tasted much championship success, but a hot spring college season led to medalist honors at his State Amateur qualifier at Cypress Ridge and to co-medalist status and the No. 1 seed this week.

Gonzalez attacked the course in the manner of the modern tour professional, using driver on every hole and bombing it as far as possible. Par 5s are the meat for going low to this player, and Gonzalez gobbled them up all week, posting birdies on five of seven in the final match (and going 7-under on the four par 5s on his near course-record 64 in the second round of stroke-play qualifying).

Wilson, who held the lead for most of the match, was unable to get his putter going, and despite laser precision with his approach shots, was unable to capitalize. “His putter was there and mine wasn’t. That was the difference,” the runner-up said. “All my bogeys were three putts. You start to lose confidence in your putter and make tentative strokes.”

Wilson is a three-time medalist at the U.S. Mid-Amateur and four-time U.S. Open participant, where he was the low amateur at the 2000 Open at Pebble Beach.

Gonzalez hit five or six drives during the lunch break and was able to right a leaky driver to start the final 18. “I found something that worked between rounds and started crushing it,” he said.

It took eight holes, but once the champion secured the lead, he methodically built toward the final margin, never losing a hole from then on. Gonzalez’s trek to the final match included four close matches, including Logan Goettsch of Fresno (2 and 1), Los Angeles’ Matt Grush (1-up), Scott Oxandaboure of Carlsbad (19th hole) and Sam Smith of Turlock (2-up).

Gonzalez dedicated the win to his recently deceased grandfather, who taught him the game. “My goal coming in was to win, and to accomplish it is huge,” he said. “To see my name among all those fantastic player, it’s quite an honor.”

Gonzalez made the first team of the Big West Conference in 2009 following a renewed dedication to his game that began in March. “I’ve tried to stay positive and started working out more,” he said after his semifinal-round win Friday. “Right now I’m riding a huge wave of confidence.”

Gonzalez finished tied for first place in the Cal Poly Intercollegiate, won the Anteater Invitational hosted by UC Irvine and finished tied for second place in the Braveheart Classic hosted by UC Riverside, all in March. He finished ninth in the Big West Conference Championships at the San Luis Obispo Country Club and qualified for the NCAA West Regional, where he finished in a tie for 57th place with rounds of 71, 76 and 74, also at Lake Merced.