Sheteron was 5-of-9 passes for 95 yards to lead the Tigers and Marco Alvarez gained 53 yards on five carries.
Branden Bosker led the Grant defense with two interceptions and a touchdown fumble recovery for a touchdown.
Rylee Schultz had eight tackles for Grant.
Gavin Porter led Shelby with 110 yards rushing on 10 carries and he was 3-of-14 passing for 38 yards.
Shelby’s Juan Cavazos had 73 yards rushing and 11 tackles.
Chris Whitlow added eight tackles and a fumble recovery, Blake Jones had an interception and Geovanni Valdez kicked a 40-yard field goal for the Tigers.