The 6-foot-4, 274-pounder helped limit GA to one first down in the first half. He leaped to bat down passes. And he tormented the Germantown Academy quarterback until the final whistle.
"It's a great start for us," Costin said. "It gives us momentum, and hopefully we can use this to get better."
Shanahan's offense was guided by quarterback Danny Murphy. The dual-threat senior rushed for 108 yards on 18 carries.
Knee and elbow injuries limited the 6-0, 178-pounder to just one practice last week. But he wasted little time in showing his speed.
Murphy rushed up the middle in the first quarter, dodged a defender, and broke free for a 43-yard touchdown.
"I'm real proud of him," Shanahan coach Paul Meyers said. "He just came out today and was a gamer."
The game-winning sack stopped GA's 10-play, 76-yard drive. The Patriots had regained possession with two minutes left after Shanahan's Kevin Stine rushed 47 yards for a touchdown to put the Eagles ahead by eight points.
GA moved with relative ease on its final drive, relying on a few big gains by Isaiah Jones and quick passes from Kyle McCloskey. The Patriots marched to Shanahan's 11-yard line and appeared set to tie the game with seconds remaining.
Then Costin struck. Meyers told the team afterward that the tackle was credited to Costin but belonged to everyone.
The defensive backs locked down the GA receivers. And the linebackers did not allow the quarterback to get outside. And that, Meyers said, allowed Costin to "do what he usually does." And on Saturday, the usual preserved a win.
Bishop Shanahan 7 0 0 7 – 14
Germantown Academy 0 0 0 6 – 6
BS: Danny Murphy 43 run (Jacob Geiger kick)
GA: Andrew Simon 3 pass from Kyle McCloskey (kick failed)
BS: Kevin Stine 47 run (Geiger kick)