The Ravens outgained the Bills 369 to 153, and Buffalo didn't make a first down until the third quarter as Baltimore's defense dominated on a rainy afternoon.
Bills quarterback Nathan Peterman was inaccurate and under pressure until being replaced by rookie first-round draft pick Josh Allen with 11:22 remaining in the third quarter. Peterman completed 5 of 18 passes for 24 yards and two interceptions while being sacked three times.
Allen was 6 of 15 for 74 yards. He ran for 26 yards on four carries and was also sacked three times.
The 33-year-old Flacco was 25 of 34 with no interceptions and threw touchdown passes to wide receiver additions Willie Snead IV, John Brown and Michael Crabtree. Rookie Lamar Jackson took over with Baltimore up 40-0 in the third quarter.
Buffalo's LeSean McCoy had seven carries for 22 yards.
The Ravens took the opening kickoff and went 80 yards in 10 plays. On second-and-26 from the Baltimore 40, Flacco hit Brown for a 29-yard gain, and Alex Collins capped the drive with an 8-yard touchdown run.
Later in the quarter, Flacco found Brown for a 7-yard touchdown.
With 5:40 left in the half, Ravens safety Tony Jefferson picked off an errant Peterman pass near midfield and returned it to the Bills' 29. Justin Tucker's 39-yard field goal made it 20-0.
Baltimore started on its own 15 after a punt late in the half, and Flacco marched them 85 yards in 2:35, capping the drive when he lofted a 12-yarder to Crabtree, who got both feet down in the back of the end zone.
Buffalo's bad day continued on the opening series of the second half when punter Corey Bojorquez fumbled the snap and Baltimore took over on the 14. Four plays later, Flacco hit Snead for a 13-yard touchdown.
The Bills avoided the shutout with a 35-yard field goal from Stephen Hauschka late in the third quarter.
Kenneth Dixon capped the scoring with a 2-yard run in the fourth quarter.
(This story has not been edited by Devdiscourse staff and is auto-generated from a syndicated feed.)