In addition to showing off his throwing prowess, Lewis also rushed three times for 15 yards, while Chase Reynolds rushed eight times for 16 yards and a score and Keith Toston added 11 yards and a touchdown. Starter Steven Jackson ran three times for seven yards.
Lance Kendricks led the air attack for the Rams, catching three passes for 73 yards and a touchdown, while Danario Alexander grabbed two balls for 48 yards and a long catch of 43 yards.
Kicker Josh Brown converted on his only field goal attempt.
First-round draft pick and Missouri standout Blaine Gabbert completed nine of his 18 passes for 132 yards for the Jaguars, while Luke McCown threw for 47 yards and a touchdown and starter David Garrard went 1-of-5 for 11 yards.
Deji Karim led the Jaguars ground attack with eight rushes for 58 yards, while starter Maurice Jones-Drew ran five times for 14 yards. Jamar Newsome led Jacksonville receivers with four catches for 83 yards and a long reception of 32 yards.
Josh Scobee connected on his lone field goal try for the Jaguars.
The teams exchanged scores in the opening half, before Toston pushed his way into the end zone from the Jacksonville one-yard line to put the Rams ahead 14-7.
Jacksonville answered with a Scobee field goal from 48 yards out to close out the third quarter.
The Rams put the game away in the fourth on a one-yard touchdown run by Reynolds and a late field goal from Brown to give the Rams a 24-17 win and perfect preseason.