KILLINGLY — Spencer Lockwood’s prowess as a running back is clear in nearly 7,000 career yards on the ground. His defensive skill helped Killingly ease its way back to the CIAC Class M football semifinals for a third year in a row.

Law, making its first appearance in the 42-year history of the playoff, scored first Tuesday night, but Lockwood ran for six scores and picked off three passes in a 57-21 quarterfinal win.

“They were everything we expected and more,” Law coach Erik Larka said. “Not a lot of weaknesses. Adjustments we made, they had a counter-adjustment.”

Law, the eighth seed, finished 6-5.

Lockwood ran for 382 yards and had scoring runs ranging from 2 to 90 yards. Three times Lockwood ran for a touchdown one play after a Law turnover.

“I didn’t care what I had. What I care about is 57-21,” Lockwood said, pointing to the far end of the field and the scoreboard. “To get to the semifinals, 11-0, it’s the best feeling.”

After its first undefeated regular season since 1953, Killingly will host fourth-seeded Berlin (9-2) in the semifinals on Sunday at 12:30 p.m. That’s the round where the Redmen stalled the past two years, losing to the eventual Class M champions both times.

Law co-captain Andrew Pawlus doesn’t expect that streak to continue.