Cody Crider's 1-yard TD in the second quarter was the only score Graves County needed in its 7-0 upset of host Bowling Green.
The Eagles (10-3) earned their first region title in school history.
The Purples (11-2) were the three-time defending Class 5A champion and had won 53 consecutive games against Kentucky opponents before falling to Graves County.
The Eagles, who started 1-3 on the season, will travel to John Hardin (7-6) to play for a bid to the state finals.
The Bulldogs, who lost five of their first six games, won 7-6 over Iroquois (11-2).
Trinity 9, St. Xavier 3: The Shamrocks earned their 12th region title since 2000 and avenged a 35-21 loss to the Tigers (8-5) earlier this year.
Meade County (11-2), last year's state runner-up, next week will host Trinity after beating previously undefeated Central Hardin 30-8 on Friday.
Dixie Heights 24, Simon Kenton 0: The Colonels (12-1) upended the Pioneers (11-2) for the second time this season, this time earning a region title for their efforts.
Dixie Heights will host Ballard in next week's semfinals. The Bruins (10-3) defeated Butler 14-7 on Friday.
Cooper 61, Anderson Co. 14: Torey Cordell rushed for 351 yards and four TDs on 31 carries to lead the Jaguars (9-4) in their blowout of the Bearcats (9-4).
Cooper will travel to Pulaski County (11-2) for next week's semifinals. The Maroons secured their second straight region title with a 24-16 win over Southwestern.
Owensboro 29, Madisonville-North Hopkins 28: The Red Devils (11-2) fended off the Maroons (10-3) after trailing 21-6 early.
Owensboro will travel to North Oldham, 47-18 winners over Fairdale on Friday, for a shot at the state finals.
Russell 17, Bourbon Co. 7: Jacob McKee and Nick Conley each scored rushing TDs for the Red Devils (11-2), who won their first region title since 2007. Russell will travel to Belfry (11-2) for a semifinals bout next Friday. The Pirates defeated Lawrence County 48-14 to win their fifth straight region title.
South Warren 36, Paducah Tilghman 0: Austin McElwain rushed for three TDs as the Spartans (13-0) blanked the Blue Tornado (7-6).
South Warren will travel to Central next Friday. The Yellowjackets (9-4) edged host Corbin 36-33 to advance to the semifinals after a penalty by the Redhounds gave Central another shot to score after time expired.
Murray 47, Caldwell Co. 28: Caldwell led 14-0 early and 28-14 in the third quarter, but couldn't fend off the visiting Tigers (9-4) after star quarterback Elijah Sindelar exited the game with an injury in the first quarter.
Sindelar, a Purdue commit who announced earlier this week he would enroll at the school in January, left the game with 1:53 left in the first quarter with an apparent knee injury after scoring a 7-yard TD to put Caldwell County (11-2) up 14-0.
Scott Sindelar, Elijah's father, told the Paducah Sun that his son's injury appeared to be a tear and that an MRI was scheduled for Monday.
DeSales (12-1), which defeated Louisville Christian 7-6 on Friday, will host Murray in the semifinals next Friday.
Shelby Valley 20, Prestonsburg 14 (OT): The Wildcats (11-2) earned their first region title after forcing a turnover on downs in the overtime to set up a Chandler Rowe score.
Shelby Valley will host Newport Central Catholic (7-5) in next week's semifinals. The Thoroughbreds defeated Newport 42-26.
Raceland 32, Paintsville 21: Josh Young scored two TDs, including a 63-yard scamper in the third quarter, to help the Rams (11-2) to their second straight region title.
Raceland will host Williamsburg (13-0), 48-14 winners over Hazard on Friday, in next week's semifinals.
Mayfield 42, Russellville 14: Trajon Bright's 66-yard TD run with 6:19 left in the game set a new school rushing mark for the Cardinals (12-1), who won their sixth straight region title.
Mayfield will travel to Beechwood (11-2) next Friday. The Tigers defeated Frankfort 46-21 to reach the semifinals.