Ravens quarterback Flacco completed 27 of his 36 pass attempts for 266 yards and two touchdowns, one each to Anquan Boldin and Vonta Leach, before being taking a seat in the third quarter.
Tyrod Taylor proved a more-than adequate replacement, throwing two touchdown passes himself and also reaching the end zone on a five-yard run. Even when Baltimore were down to their third-stringers they still scored, Curtis Painter hitting Tommy Streeter on a 33-yarder in the final minute.
The Jaguars, who saw both cornerback Aaron Ross and tight end Zach Miller forced out of the action through injury, made the final score a little more respectable thanks to 14 fourth-quarter points, seven of them coming on an interception return by Antonio Dennard.
Elsewhere, quarterback Aaron Rodgers rushed for two touchdowns to help theGreen Bay Packers see off the Cincinnati Bengals by a 27-13 scoreline at Paul Brown Stadium.
Rodgers reached the end zone on rushes of 12 and five yards in the first quarter and ended up finishing the contest as the leading runner on either team, managing 52 yards on six carries.
The Packers opened up a comfortable 17-6 half-time lead and Jamari Lattimore sealed the win with a 27-yard interception return for a TD in the fourth quarter.
Former Bengal running back Cedric Benson managed 38 yards for the Packers against the team that opted not to keep hold of him in the off-season. Cincinnati managed just 195 yards of offence in the game.
Jake Locker showed just why Tennessee has chosen him as their starting quarterback for week one of the regular season with an impressive display in the Titans' 32-27 victory over the Arizona Cardinals.
The second-year pro connected for scores with wide receivers Kendall Wright and Nate Washington to help the Titans open up a 17-10 half-time lead.
For the Cardinals, John Skelton started under centre but struggled, managing just 41 yards on four completions. Kevin Kolb, Skelton's rival for the starting job, faired a little better in the second and third quarters, though he was sacked twice and picked off once.