Gilder, who has won four of his last seven starts, also picked up back-to-back wins in late July with victories at the SBC Senior Open and the FleetBoston Classic.
'A combination of things have been coming around for me during this stretch,' said Gilder. 'It's hard to put into words winning two back-to-back events in seven weeks.'
More from Gilder on his win.
The 51-year-old brought a slim one shot lead into the final round and fought hard to maintain the margin. However, after Tom Jenkins torched the TPC at River's Bend with a course-record-matching 62 on Sunday to finish regulation tied with Gilder at 16-under-par 200, it was time for a playoff.
The duo walked back to the 18th tee to begin the extra session and both players knocked their tee shots down the fairway of the par-5. Gilder sent his second shot into the trees right of the green while Jenkins left his second in front of the putting surface.
Jenkins chipped his third to 20 feet with Gilder leaving himself 45 feet from the hole after his third shot. Both players two-putted for par to continue the playoff.
At the second extra hole, the par-4 10th, Gilder put himself closer to the win with a brilliant approach that dropped two feet from the cup while Jenkins hit his second shot 10 feet from the hole. Gilder converted for birdie and the win as Jenkins pushed his birdie try one foot past the cup.
Of Gilder's four victories this year, three of them have come in playoffs. The win is Gilder's sixth since joining the Senior Tour in 2000.
'I couldn't believe I was winning coming into the last day,' said Gilder, who carded a final-round 69. 'I'm fortunate I won. I didn't think 69 would get me in a playoff. I thought I'd have to go lower.'
Jenkins was on fire with 10 birdies and no bogeys for his best career round on the Senior Tour.
'How can you complain,' said Jenkins, who lost this event in a playoff to Jim Thorpe last year. 'It's disappointing to get this close and lose but it will keep me coming back here with determination.'
Hale Irwin was flawless as well with eight birdies and no bogeys for a round of 64. The 57-year-old edged his way into third place at 15-under-par 201, his 16th top-five finish of 2002.
Bruce Lietzke was the first to fire a 62 on Sunday. He picked up 10 birdies without a bogey to establish the new course record, which was later equaled by Jenkins. Lietzke finished at 13-under-par 203 alongside Tom Kite.
Larry Nelson, who finished second at this event in 2000, was one shot further back along with Ed Dougherty at 12-under-par 204.
Last year's winner Jim Thorpe put together a strong finish with an 8-under 64 to join Bruce Fleisher, Ben Crenshaw, Gil Morgan and Andy North at 11-under-par 205.
Final results from the Kroger Senior Classic