"It felt great out there tonight," Bradford said. "I felt like we really got in a rhythm early as an offense. We were able to go down and score on our first drive. We converted on a couple of third downs, which is always nice. It was really a great first drive."
Bradford completed all six of his pass attempts, including a 36-yarder to Danny Amendola along the left sideline, and capped off the 10-play, 75-yard drive with a 2-yard touchdown pass to tight end Billy Bajema.
In four preseason games, the rookie quarterback from the University of Oklahoma completed 60 percent of his passes (33 of 55) for 338 yards and three touchdowns without an interception.
Second-year quarterback Keith Null entered the game for the Rams second series and led the team on an eight-play, 79-yard scoring drive. His 3-yard touchdown pass to Brandon Gibson gave St. Louis a 14-0 lead.
The Ravens (3-1) scored early in the second quarter when linebacker Dannell Ellerbe returned a Null interception 57 yards for a touchdown to make it 14-7.
St. Louis added a 45-yard field goal from Josh Brown with 4 minutes and 2 seconds left in the second quarter to take a 17-7 lead.
The Rams led by the same score after halftime after the defense kept the Ravens out of the end zone on a fourth-and-goal situation from the 1-yard line when a Troy Smith pass was tipped and intercepted by Chris Chamberlain and returned 83 yards before he was caught from behind.
Smith led Baltimore on an 80-yard scoring drive to start the second half and capped it off with a 1-yard touchdown dive to make it 17-14.
Brown added a 54-yard field goal with 2:02 remaining in the third quarter to put the Rams in front 20-14.
The Ravens cut the lead to 27-21 on a 2-yard touchdown run by Smith with 3:41 remaining and had a chance to pull out a last-second victory, but Smith's pass to the end zone as time expired was knocked away.
The Rams offense gained 370 yards on the night, including 237 through the air, while the Ravens racked up 304 yards.
Null completed seven of his 10 passes for 90 yards, with one touchdown and one interception. Lewis completed six of his eight passes for 89 yards and a touchdown.
Rookie Keith Toston rushed for a team-high 47 yards on 10 carries. Kenneth Darby, who started in place of Steven Jackson, carried six times for 39 yards. Chris Ogbonnaya gained 31 yards on 16 carries.
Brandon Gibson was the Rams' most productive receiver on the night. He hauled in four passes for 40 yards and a touchdown. Tight end Daniel Fells caught two passes for 27 yards, while rookie tight end Fendi Onobun had two catches for 23 yards.