BALTIMORE (AP) -- Joe Flacco threw a touchdown pass before being knocked from the game with a concussion, and the Baltimore Ravens frustrated quarterback Matt Moore and the Miami Dolphins in a 40-0 victory Thursday night.
Alex Collins ran for a career-high 113 yards, and Baltimore (4-4) returned two interceptions for touchdowns in the most lopsided shutout in franchise history.
In the midst of one of his best performances of the season, Flacco was struck in the helmet by Miami linebacker Kiko Alonso while sliding at the end of an impromptu run. Flacco's helmet flew off his head, and the 10-year quarterback appeared dazed as he struggled to his feet.
The play occurred with 3 minutes left in the second quarter. Alonso was flagged for unnecessary roughness, providing Baltimore with a first down that ultimately turned into a touchdown.
Flacco was initially placed in concussion protocol, and by halftime was ruled out.
He went 10 for 15 for 101 yards, including a 34-yard touchdown pass to Jeremy Maclin.
After losing four of five to fall under .500 for the first time this season, the Ravens put it all together with a showing that included a 63-yard interception return by C.J. Mosley and a 50-yard pick-six by Jimmy Smith.
The Dolphins (4-3) came in with a three-game winning streak after rallying from 17- and 14-point deficits in the previous two weeks. There would be no comeback in this one, not against a swarming Baltimore defense that limited Miami to 196 yards.
Moore was making his first start of the season, for the injured Jay Cutler. Four days earlier, Moore engineered a victory over the Jets after Cutler left with fractured ribs.
In this one, Moore completed 25 of 44 passes for 176 yards. He received little backing from the running game, which generated only 45 yards against the 32nd-ranked rushing defense in the NFL.
Baltimore went up 7-0 when Maclin slipped behind Bobby McCain and Nate Allen to haul in Flacco's perfect pass on the right sideline.
Justin Tucker added field goals of 55 and 48 yards in the second quarter. After Cody Parkey missed from 50 yards for the Dolphins -- his first misfire in nine tries this season -- Flacco began the drive that would end in the end zone without him.
The late hit by Alonso gave Baltimore a first down at the Miami 5. Three plays later, Ryan Mallett threw a 2-yard TD pass to Benjamin Coleman.
Mosley iced it with 14:15 left when he snared a poor throw by Moore near the line of scrimmage and turned it into his first career interception return for a touchdown.
As the Ravens were closing in another score, a few players exchanged shoves and punches before Chris Moore pounced on a fumble in the end zone.
Overseeing an offense focused on protecting a sizable lead, Mallett went 3 for 7 for 20 yards.
Dolphins: Allen hurt his calf in the second quarter and did not return.
Ravens: TE Vince Mayle was placed in concussion protocol in the second quarter. … LT Ronnie Stanley hurt his shoulder in the third quarter but returned to action.
Dolphins: Miami plays the second of three straight night games, this one at home against Oakland on Nov. 5.
Ravens: Baltimore faces Tennessee on the road on Nov. 5, the first meeting between the teams since 2014.