4. Nov. 1, 1980, vs. UTEP
The Miners didn't pose much of a test for McMahon, and the Cougars set a new Western Athletic Conference and school scoring record, according to BYUCougars.com, as BYU destroyed UTEP 83-7. In the massive win, he completed 28-of-36 passes for 451 yards and six touchdowns against just one interception, including a pair of touchdown throws to both Clay Brown and Scott Phillips. As part of his big passing day, McMahon threw for 372 yards in the first half alone, according to BYUCougars.com.

5. Oct. 18, 1980, vs. Utah State
Many consider the game against the Aggies as his best game ever, and it probably would have been had he not thrown three interceptions. In the 70-46 win, he completed 21-of-33 passes for 485 yards and six touchdowns. He also added 10 carries for 31 yards and two rushing touchdowns for the eight-score day.

Not to mention the Miracle Bowl later that year