The other two guys, however, also put on quite a show.
Baltimore (2-0) led 17-0 after the first period and cruised to the finish against the Rams (0-1), who rested offensive stars Jared Goff and Todd Gurley.
After sitting out the Hall of Fame Game last week, Flacco went 5 for 7 for 71 yards during a 10-play drive. The 11-year veteran overcame a second-and-25 with a 30-yard pass to newcomer Michael Crabtree and finished with a 6-yard TD throw to Patrick Ricard.
"That's really all we needed from Joe," coach John Harbaugh said. "Get Lamar out there with a lot of reps, get Robert (Griffin III) out there."
Jackson entered the next time Baltimore got the ball and coolly directed a 73-yard march in which he completed a 36-yard pass to Chris Moore and broke two tackles running for a 9-yard touchdown.
"It was a great run," Harbaugh said. "I thought he was tackled twice -- and then he wasn't."
Said Jackson: "They tried to get to me, I made a guy miss. Then I did what I do best and tried to get in the end zone."
Jackson went 7 for 18 for 119 yards, ran for 21 yards and was sacked twice before giving way to Griffin early in the third quarter.
Griffin went 5 for 7 for 88 yards, including a 32-yard touchdown strike to Breshad Perriman.
Flacco has been named Baltimore's starter in the regular season. Griffin is seeking a comeback after being inactive in 2017, and Jackson is trying to adjust to the pro game after winning a Heisman Trophy at Louisville and being drafted in the first round last April.
Jackson could learn a thing or two by watching Flacco.
"He was awesome. He was smooth, had a lot of poise in the pocket," the rookie said.
The Ravens and Rams held joint practices Monday and Tuesday, and Los Angeles coach Sean McVay indicated the work against outside opposition would enable him to rest a few of his starters in the preseason opener.
Los Angeles gained 5 yards and made one first down in the first quarter. The Rams trailed 23-0 at halftime after totaling 45 yards and three first downs.
"We expect to play better and we will," McVay said. "Sometimes these lessons, these humbling experiences if you will, for everybody is the level of awareness. You can't wait to get back to work and know that we got a lot work to do. What's encouraging is we have time to figure it out."
Mannion played the first half, going 3 for 13 for 16 yards and an interception.
"It certainly wasn't my best performance. Just wasn't really able to get into a rhythm early," Mannion said.
Both teams stood during the national anthem. While most of the Ravens lined up shoulder to shoulder on the sideline, second-year linebacker Tim Williams stood alone in front of the bench with his back toward the field.
It appeared as if both teams got out of the game without any significant injuries.
The Rams received successive 15-yard penalties in the first quarter for lowering the head to initiate contact, a new rule this season. Marqui Christian received the first flag, and Blake Countess followed. The penalties attributed for nearly half the yardage in a drive that produced a field goal for a 17-0 lead.
"The preseason offers a great opportunity for all of us to work through some things and learn," McVay said. "How that can enable us to better coach it, and how we can better understand, how we can expect them to consistently officiate that knowing that most importantly it's about taking the head out of the game."
Rams: After an extended stay on the East Coast, Los Angeles heads home to begin preparation for its next opponent, the Oakland Raiders at home on Aug. 18.
Ravens: Their next preseason game isn't until Aug. 20 at Indianapolis, but that begins a stretch of three games in 11 days.
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