Dak Prescott threw for four touchdowns and rushed for another as the Dallas Cowboys steamrolled the New York Giants 49-17 on Sunday in Arlington, Texas.Prescott completed 26 of 35 passes for 404 yards and was picked off once. He has now thrown for at least 400 yards and four scores three times in his career, marking a Dallas franchise record.Brandin Cooks and CeeDee Lamb carved up the Giants’ secondary, with Cooks grabbing nine catches for 173 yards and a touchdown. Lamb finished with 11 receptions for 151 yards and a TD.Rico Dowdle led the Cowboys’ rushing attack with 79 yards and a TD on 12 carries.In his first career NFL start, New York quarterback Tommy DeVito threw for 86 yards with two touchdowns and an interception on 14-for-27 passing. He was sacked five times.Saquon Barkley rushed for 66 yards on 13 touches for New York (2-8), which was outgained 640-172 and failed to convert on all 12 of its third-down attempts as it struggled to break through a stiff Dallas defense.After Lamb rushed for a 14-yard touchdown on a reverse to open the scoring with 3:38 left in the first quarter, Prescott helped the Cowboys (6-3) break the game open in the second.He threw a 1-yard scoring strike to Jake Ferguson before finding Cooks for a 10-yard TD to make it 21-0 with 3:48 left in the first half. Then, with just 16 seconds remaining until the break, Prescott used his legs to get into the end zone from 10 yards out.