Garrard (9-2) had to fight back after DeSales (5-6) took a 15-12 lead on a touchdown with 52 seconds left.
While the Colts and their fans were celebrating on the far side of Dyehouse Stadium, Stonebraker made sure his players knew they still had time to answer.
"I told them we had just enough time," Stonebraker said. "We knew that was enough time to get us a score. The other thing we had to do was believe, and evidently our kids did that."
That's something the Lions might not have done in the same situation a year ago, but they said a handful of close regular-season wins left them better prepared for this scenario.
"I think it prepared our minds a great deal," Cool said. "Last year at times like this we quit."
"That's a major difference from last year's team: Everyone steps up and plays hard," Williams added.
They'll be playing again this Friday when Garrard visits Elizabethtown, a 58-12 winner over Wayne County, for a second-round game.
Garrard won despite committing four turnovers, including giveaways on three straight series before the winning drive.
Williams was 17-for-27 for 184 yards, but he threw three interceptions in the second half.
"No one got down on me," Williams said. "Everyone on the sideline tried to cheer me up."
"You've got to give Bruce credit for fighting back and making the plays he made on the last drive," Stonebraker said.
The Lions' comeback allowed Cool to redeem himself, too. He had been beaten by DeSales receiver Keith Belt in the end zone when the Colts took the lead.
"I was feeling like the goat after that," he said.
But when Cool caught the winning pass, he got in front of Belt to make the play.
"We got a lot of great protection, and Bruce made a great pass," said Cool, who had 11 receptions for 115 yards.
"(Belt) had made some great plays the whole game, and I knew I had to go up for the ball and make a play."
"I figured he'd be able to go up and get the ball," Williams said. "That's Jake for you. He's done it all year."
Williams and Cool hooked up five times on decisive drive
Williams and Cool hooked up five times for 46 yards on the decisive drive in which Garrard needed just 39 seconds to cover 70 yards in six plays.
"We didn't plan to do that really at the start of the drive," Stonebraker said. "They were giving us a look where we were going to be able to pick on that side."
Another key play in the drive came from DeSales defensive lineman Anthony Bradford, who gave a Garrard player an emphatic shove that drew a flag for unsportsmanlike conduct in conjunction with an offsides penalty.
The penalty yards moved the ball from DeSales' 46-yard line to the 27, from which Garrard would score in just three plays.
DeSales needed only three plays to score after Garrard's second turnover in 25 seconds gave the Colts the ball at the Garrard 48 with 1:24 to play.
The first of those two turnovers killed a drive in which the Lions ate up over six minutes.
They got the ball back 12 seconds later on the last of DeSales' four turnovers, only to give it away again
Garrard took a 7-2 lead late in the first quarter on a 16-yard run by Tim Quisenberry, who rushed for a game-high 54 yards.
A 34-yard field goal by Cory Horn made it 10-2 before DeSales scored its first touchdown in the closing seconds of the first half.
The Lions took a 12-8 lead on a safety late in the third quarter when Quisenberry tripped up DeSales quarterback Garrett Reed in the end zone.
DeSales was stopped in Garrard territory three times in the second half, and the Lions allowed just 40 yards rushing.
"Our defensive front played well," Stonebraker said. "That's one of the best jobs anybody's done on them all year."