The 38-year-old Fritsch shot a 1-under 71 in windy conditions to match Schniederjans at 11-under 277 at TPC Cartagena at Karibana. Fritsch earned $126,000 to jump from 108th to fifth on the money list with $129,790, with the top 25 at the end of the regular season earning PGA Tour cards.
"This is huge," Fritsch said. "My whole golfing life I haven't won a lot. This is easily the biggest win against the best field that I've ever faced. Obviously, it gives me a nice jump on getting my card for next year. To do something I've never really done before and to execute under pressure on 18, I love it.
I want that feeling again."
The 22-year-old Schniederjans had a 69, then made a triple-bogey on the par-5 18th in the playoff. He pulled his drive left into the water, and also hit his third into the hazard.
"I'm bummed that I didn't get this one but it was a good experience, getting to play 18 holes on Sunday right there by the lead," Schniederjans said. "I made some good putts and did really well just to get into this playoff. I hit an OK drive and it just went through and into the water."
Fritsch hit a 220-yard shot to 20 feet to set up his winning three-putt par.
"I wasn't exactly sure what was going on, but I hit a great shot," Fritsch said. "This time, I hit the 4-iron, figuring that if I could get that on and two-putt, he would have to get it up-and-down."
Tag Ridings was third at 9 under after a 69.