The Bulldogs took a 6-0 lead in the second quarter on a 28-yard pass from Trevor Westhoff to Tyler Borchers.
Matt Ellefson doubled the lead on a 56-yard run later in the second quarter. Le Mars led 12-0 at halftime.
The Bulldogs scored for the final time in the fourth quarter on a 24-yard pass from Westhoff to Cory Niehus. Judd Bagstad set the final score on an extra point kick.
Le Mars ran 59 plays on offense and limited Spencer to just 30 plays. The Bulldogs gained 296 yards of offense and stifled the Tigers' offense, which gained just 48 yards.
Le Mars converted on five out of 14 third downs and four out of six fourth downs. Spencer finished 0-for-7 on third downs and 0-for-1 on fourth down.
Westhoff was 10-for-17 passing for 126 yards, two touchdowns and one interception.
Borchers caught three passes for 52 yards and a touchdown. Beau Ohm made three catches for 41 yards. Niehus' touchdown was his only catch.
Borchers made three solo tackles and assisted on two more. Mitchell Mullally made two solo tackles and four assisted tackles. Alex Sudtelgte made two solo tackles and three assisted tackles. Borchers had 1.5 tackles behind the line of scrimmage. Mullally and Sudtelgte each assisted on a tackle behind the line of scrimmage.