Manziel matched a career high in TD passes and completed 30-of-39 throws as the Aggies (8-2, 4-2 SEC) notched the the 700th victory in school history.
Malcome Kennedy and Travis Labhart each made two scoring grabs.
The Bulldogs (4-5, 1-4) got three TD passes from Dak Prescott, who was playing just days after the death of his mother. He went 15-of-27 for 158 passing yards with an interception, while also rushing for 154 yards on 16 carries.
Tyler Russell took over behind center in the fourth quarter and fired a scoring pass.