With the Southland Conference's top-rated defense, the Cowboys (5-0, 4-0) held the Lions (3-2, 2-1) to 59 yards rushing and forced two fumbles while generating 369 yards of total offense.
Sams scored on a 3-yard run on McNeese State's opening drive and Ross scored on a 58-yarder on the second drive for a 14-0 Cowboys lead.
The Lions struck back when D'Shaie Landor hit William French with a 54-yard pass and a personal foul penalty moved the ball to the McNeese State 1-yard line. Xavier Roberson ran it in on the next play.
Ross gave the Cowboys a 21-7 halftime lead after a 4-yard TD run and had rushed for more than 100 yards before the intermission. He finished with 15 carries.