The Cowboys evened their Super Bowl record at 2-2 by defeating Denver before a sellout crowd of 75,583, plus 102,010,000 television viewers, the largest audience ever to watch a sporting event.
Dallas converted two interceptions into 10 points and Efren Herrera added a 35-yard field goal for a 13-0 halftime advantage.
In the third period Craig Morton engineered a drive to the Cowboys' 30 and Jim Turner's 47-yard field goal made the score 13-3.
After an exchange of punts, Butch Johnson made a spectacular diving catch in the end zone to complete a 45-yard pass from Roger Staubach and put the Cowboys ahead 20-3.
Following Rick Upchurch's 67-yard kickoff return, Norris Weese guided the Broncos to a touchdown to cut the Dallas lead to 20-10.
Dallas clinched the victory when running back Robert Newhouse tossed a 29-yard touchdown pass to Golden Richards with 7:04 remaining in the game. It was the first pass thrown by Newhouse since 1975.
Harvey Martin and Randy White, who were named co-most valuable players, led the Cowboys' defense, which recovered four fumbles and intercepted four passes.