"He's a senior who needed to step up, and he did in every shape and form," Saints rookie coach Kevin Schneider said.
The second game of the series - Neumann-Goretti also won via the 10-run mercy rule in Wednesday's opener - was switched to La Salle because Widener's field was deemed unplayable after the heavy rain and hail that fell Thursday.
It was the third Catholic League crown for Ockimey, who is ticketed for Indiana, and the Marist-bound Jerla.
"It's my senior year, so that makes this one the best," Ockimey said.
Jerla, a lefthander and the squad's No. 2 pitcher, limited Roman to four hits. The 6-foot-2, 185-pounder mixed a fastball that has been clocked at 86 m.p.h., curveball, and change-up.
"Everything was working really well for me," said the 18-year-old, who lives in South Philly. "My bullpen felt awesome."
It was Jerla's second straight stellar outing. In a loser's-bracket contest last Saturday against La Salle, he allowed only four hits and fanned five in a 1-0 triumph at 26th and Moore.
"That was one of the gutsiest performances I've seen," Schneider said.
Jerla walked two of 21 batters and threw 80 pitches, with 56 for strikes, in Friday's rematch with Roman. He whiffed four in the first two innings.
"He loves to compete," Schneider said. "That's something he does that is real, from the heart, and makes him successful."
The Saints (20-4) took control with a four-run third inning highlighted by Jerla's two-run double to right-center field. They tacked on seven runs, on only two hits, in a fourth inning that included RBI singles from Pat Doudican and Brian Verratti.
The Cahillites (11-12) ran out of gas after going 3-0 to start the playoffs. After posting a 7-8 mark in the Red Division during the regular season, they nearly won their first league title since 1992.
Roman Catholic 000 00 - 0 4 2
Neumann-Goretti 004 7x - 11 6 0
WP: Charlie Jerla. LP: Joe Mangano. 2B: RC-Mike Opiela, Conor Smith; NG-Jerla.