Davis, a 6-foot-4, 190-pound forward, shot 5 for 6 from the field - his only miss was from beyond the three-point arc - and 9 for 12 at the foul line. He added five blocks.
"I'm trying to improve my overall game," he said. "Another thing I want to do is be a better team leader. I think that's important."
On Friday, at 8 p.m. at Penn State's Bryce Jordan Center, the Saints (27-3) will try for their third state title when they face Montour, District 7's fourth-place qualifier.
Neumann-Goretti gained redemption for a lackluster showing against Boys' Latin in the District 12 final. Carl Arrigale's squad prevailed, 66-57, after trailing by two at intermission.
"We were excited about playing them again," Arrigale said. "We felt like we didn't play our best game the first time."
In eliminating the Warriors (25-7), the Saints also put an end to Maurice Watson's stellar career. With 18 points, the senior guard finished with 2,356, the seventh-best all-time mark in Southeastern Pennsylvania.
Arrigale assigned Hanif Sutton and sub La'Quan Coaxum to keep tabs on the Boston University recruit.
"We knew Maurice and two other guys [junior guard Yahmir Greenlee and 6-3 senior forward Carlos Taylor] took the bulk of their shots," Arrigale said. "That was our focus."
Greenlee, guarded by Billy Shank, went scoreless in the first half and finished with five points. Taylor, with 6-6 forward Derrick Stewart and Ja'Quan Newton close by, managed only a second-quarter bucket.
Newton, a sophomore, equaled Davis' 19 points, and added seven boards and three assists. The Rider-bound Stewart totaled eight points and the same number of boards.
Late in the second quarter, layups by Coaxum and Newton put Neumann-Goretti in front, 34-21. Watson's pull-up jumper left the halftime difference at 11.
In the third period, Shank's steal and layup pushed the lead to 44-25. Later, Davis' layin and follow shot pushed it to 50-29.
Boys' Latin 11 12 12 8 – 43
Neumann-Goretti 16 18 18 22 – 74
BL: Maurice Watson 18, Yahmir Greenlee 5, Carlos Taylor 2, Eric Lark 2, Rashan Wooten-Miller 11, Khadafi Robinson 5.
NG: Hanif Sutton 4, Billy Shank 13, Derrick Stewart 8, John Davis 19, Ja'Quan Newton 19, La'Quan Coaxum 4, Lamar Kimble 3, Troy Harper 4.
Contact Rick O'Brien at firstname.lastname@example.org or @ozoneinq on Twitter.