The Tigers fell behind early and just could not muster any offense, while the Bobcats looked sharp, converting on 12 out of 13 third down attempts in the ballgame.
"They made plays and we didn't and they won the game," said MCHS head Coach Tom Turchetta. "We knew what they were going to do, but every time we got them in third and long and fourth and medium they dinked us and got a first down."
After Marshall County punted away their first possession, Giles County marched 71 yards on their first touch to take a 7-0 lead.
Bobcat quarterback Al Cobb went 4-5 in the drive that was capped off with a Cobb 7-yard touchdown toss to Darren May with 1:43 remaining in the first quarter.
The Tigers could not solve the Bobcat defense and had to punt again after three plays.
Giles County proceeded to drive down the field, as Cobb hooked up on a third and six and a fourth down and ten to wide receiver Ben Bates before finding Kenton Baker for a score from the Tiger five-yard line.
Clay Whetsel added his second extra point kick of the ballgame to give Giles County a 14-0 lead with 6:33 remaining in the first half.
Marshall County went to their bread and butter on their next series, handing the ball to record setting tailback Trevor Irizarry on 10 out of 12 plays before the drive stalled at Bobcat 5-yard line.
Turchetta decided to attempt a 22-yard field goal with 37.4 seconds left in the first half, but the usually reliable Aaron Medley hooked the ball left of the goal posts and a kneel down by Cobb one play later gave the Bobcats a two touchdown lead at the intermission.
Both squads punted away their first possessions of the second half , and on Giles County's next touch, the Bobcats drove all the way to the Marshall County 20-yard line before Tiger senior linebacker Dusty Nance came up with a fumble recovery to end the march.
Unfortunately, the hometown Tigers could not take advantage of the Giles County turnover and were forced to punt at the end of the third quarter.
The Bobcats held on to the ball on their next series that lasted just seven plays before Delvin Pope found the end zone from 1-yard out to make it 21-0 with 10:01 remaining in the contest.
The Tigers (9-4) would not respond and punted the ball back to the Bobcats, who put the game on ice with an eleven-play scoring drive, capped off by a De De Coffey six-yard scoring jaunt.
"I believe our best football is ahead of us, but we had a great group of seniors that stepped up and led our football team and put us in position to do something special," said Turchetta. "I hate for them that it did not come to fruition. I didn't get it done the way it should have been done and I take the full blame for that, but we will be back."
Irizarry (22 rushes for 82 yards in the game) ended his record setting season with 2,038 rushing yards, becoming the first Tiger running back to eclipse the 2,000 yard mark in a single season.
Giles County (10-3) travels to Greenville (12-1) in next week's 4A semifinal.
Greeneville, who lost the title game to Giles County in 2009, is seeking their third straight trip to the Blue Cross Bowl championship game in Cookeville.