The game was delayed 30 minutes because of lightning late in the third quarter.
Newton went 8 of 12 before leaving midway through the second period. He opened the game by leading a 93-yard drive that included Ted Ginn Jr.'s 61-yard touchdown reception.
That opening series also featured two completions to Kelvin Benjamin, who missed the 2015 season with a torn left anterior cruciate ligament after catching 73 passes for 1,008 yards and nine touchdowns his rookie season. Benjamin caught a 16-yard pass on the game's first play from scrimmage and had a 13-yard reception on a third-and-7.
Mariota is 14 of 15 through two preseason games.
Copyright 2016 by The Associated Press