Lamar could not slow SHSU's rushing attack as the Bearkats totaled 268 yards. Jalen Overstreet ran for 132 yards on nine carries.
The Bearkats responded quickly when Johnson passed to Gerald Thomas from the 22 for a score and a 26-10 advantage.
Overstreet dashed 50 yards for a score in the fourth to seal the victory.
Berry threw for 244 yards and one touchdown for Lamar (3-2, 0-1).