In the second half, when Roman pulled away from O'Hara, Kelly netted 181 yards on 15 attempts. He totaled 143 yards on 14 tries before intermission.
Tackling the 5-foot-9, 170-pounder can be as difficult as getting him to talk about his rushing prowess.
"He doesn't talk at all," Roman teammate Taishan Tucker, a receiver and free safety, said with a laugh. "That's Marcus. He's pretty quiet."
In the first quarter, Kelly, a senior captain who is hearing from the likes of Lafayette (McCourt's alma mater) and Lehigh, went off right tackle and raced 30 yards for the first of his three touchdowns.
The 17-year-old, who played youth football for the Wissahickon AA Braves, set up the score with bursts of 19 and 23 yards.
"He does it all," said McCourt, a 3,300-yard career rusher for the Cahillites. "He makes the first guy miss, speeds through the hole, and he can lower the boom. Don't be deceived by his size. He can run people over."
In the third quarter, on a left-side counter play, Kelly, who doubles as a strong safety, produced a 12-yard TD run.
Midway through the fourth quarter, with Roman ahead by 26-14, Kelly made his way to the right sideline and, after escaping a pair of would-be tacklers at the O'Hara 40-yard line, notched a 57-yard score.
"My coach [McCourt] told me I would have a big day," Kelly said. "With them expecting us to pass, he thought we'd have to run the ball a lot."
In humid conditions, the Cahillites (3-1) managed 391 rushing yards. The offensive line included center Mike Joyce, guards Roberto Harris-Barron and Collin Shields, and tackles Steve Noel and Tyrone Brown.
Roman's defense held the Lions (2-1) to 49 yards rushing and 12 passing. Kelly (five tackles), Tucker (four), end Jon Upchurch, and linebackers Brett Pellicciotti and Guy Campanella were among the leaders.
Kelly's brother, Dimetri, a freshman two-way back, sat out the game with an ankle injury.
"The coaches wanted to play it safe with him," Marcus Kelly said. "He should be back next week."
Roman Catholic 7 13 6 7 – 33
Cardinal O'Hara 7 7 0 0 – 14
CO: Shaw 40 run (Weyler kick)
RC: M. Kelly 30 run (Isaac kick)
RC: Fuller 11 pass from Keir (Isaac kick)
CO: Dunbar 99 interception return (Weyler kick)
RC: Keir 1 run (kick failed)
RC: M. Kelly 12 run (pass failed)
RC: M. Kelly 57 run (Isaac kick)
Contact staff writer Rick O'Brien at 610-313-8019, robrien@phillynews.com, or @ozoneinq on Twitter.
