The Leopards constantly pressured on defense from the interior and kept Rebels QB David Miner on the run.
"Coach (Buddy Orndorff) talked to us in practice about keeping pressure on (Miner)," said defensive end Mike Trueblood, one of several seniors honored in their final home game. "This was a big game for us for the playoffs. Coach told us we could do it if we kept our heads."
Road games at North Hagerstown and Boonsboro remain for Smithsburg, and Orndorff took caution for the future with the proverbial "we'll take one week at a time."
"We'll look at film and give the kids a game plan," Orndorff said. "I thought they worked very hard tonight and that we dominated the line of scrimmage."
From the opening kickoff, Smithsburg took 7 1/2 minutes off the clock with an all-ground attack that gained 59 yards on 14 plays before the Rebels held on downs at the 1-yard line when White was stopped on fourth down.
However, the Leopards defense forced a quick three-and-out.
With punter Josh Bussard hemmed in with minimal punting room, Josh Talbert was one of several penetrating Leopards that broke through the line. Talbert got his hands on the punt and defensive end Mike Trueblood found the loose pigskin for a six-pointer.
South (3-5, 2-2) had two possessions in the second quarter and each ended with an interception by Bowser, the second pick with 2:20 left in the first half that gave the Leopards short field position at the Rebels' 35.
A key 18-yard gain by White, with four Rebels trying to bring him down, put the ball on the 1 and QB Nathan Steelman sneaked over for the score with 26 seconds left in the half.
At that point, Smithsburg had run 36 plays for 158 yards to 16 plays and 23 total yards for South, which reached the Leopards 47 for its best penetration offensively.
Things didn't get any better for South in the second half.
A Smithsburg short-kick effort caught South off guard and the Leopards went to work offensively from the Rebels 42.
The Leopards converted a pair of fourth downs and used a 13-yard run on a textbook sweep right by White to get in the red zone.
After two short losses, Steelman went into a shotgun formation, rolled left with some pressure on him and zipped a pass to Bowser, waiting for ball between a pair of South defenders.
The Rebels even went on a 17-play march that consumed nine minutes and got them to the Smithsburg 13, but a pair of penalties and two rushing losses took the zip off the drive.
Smithsburg put the capper on the night with a quick 81-yard drive in seven plays when White rambled 49 yards on a pitchout from Steelman on the short side of scrimmage, broke two tackles and found daylight.
Bowser's two picks gave him six for the year.
"He missed last year because of a shoulder injury and he's a big bonus to us for being here this year," Orndorff said. "He's been solid all year and is a big leader on our defense."
White's yardage came on 31 efforts as the Leopards totaled 288 yards offensively.
Antwan Jones picked up 54 yards on nine carries for South, which had a mere 93 yards on the ground.
"We were surprised at their defensive pressure," Kellick said. "They pressured the middle and came hard at us and we didn't respond."