INGLEWOOD, Calif. (AP) — Matthew Stafford passed for 321 yards and three touchdowns in a dynamic debut with his new team, leading the Los Angeles Rams past Andy Dalton and the Chicago Bears for a 34-14 victory on Sunday night.

Stafford found Van Jefferson for a 67-yard touchdown on his second pass for the Rams, who swung a blockbuster offseason trade to acquire the 13-year veteran quarterback from Detroit. Stafford then hit a wide-open Cooper Kupp for a 56-yard TD to open the third quarter, and he found Robert Woods for a clinching score with 3:17 to play.

What You Need To Know

  • The Rams defeated the Bears 34-14 Sunday night at SoFi Stadium

  • Matthew Stafford  passed for 321 yards and three touchdowns in his Rams debut

  • According to the Elias Sports Bureau, Stafford became the first player with two touchdown passes of more than 50 yards in his debut for a new team since Lee Grosscup did it for the AFL’s New York Titans in 1962

  • Up next: road opener against the Indianapolis Colts on Sunday

With Stafford in place of Jared Goff, the Rams again looked like the offensive powerhouse of their first two seasons under coach Sean McVay, who improved to 5-0 in season openers. The Rams scored on six of Stafford's first seven full drives while racking up 375 yards of offense, and Kupp finished with seven catches for 108 yards.

Dalton passed for 206 yards in his Bears debut, and rookie quarterback Justin Fields rushed for a 3-yard score while getting a handful of snaps in his NFL debut. Chicago moved the ball steadily, but Dalton's end-zone interception after a solid opening drive left the Bears playing from behind all night.

David Montgomery rushed for 108 yards and a touchdown for the Bears, who dropped to 1-3 in season openers under coach Matt Nagy.

Dalton has begun his Bears career in a competition with Fields, the touted Ohio State rookie who looked impressive in the preseason. Nagy used both quarterbacks against the Rams, intermittently substituting Fields from the opening drive onward. Fields completed both of his passes for 10 yards.

But Stafford was the center of attention in the first regular-season NFL game with fans at palatial SoFi Stadium, which opened last year. The 33-year-old quarterback left the Lions six months ago for Los Angeles, which traded Goff and two first-round picks to acquire an undeniable talent with no career playoff victories and everything to prove.

According to the Elias Sports Bureau, Stafford became the first player with two touchdown passes of more than 50 yards in his debut for a new team since Lee Grosscup did it for the AFL’s New York Titans in 1962.

Stafford opened his Rams career with his long, beautiful throw to Jefferson on his third offensive snap. The ball hung 53 yards in the air and dropped straight to Jefferson, who fell, rose and scored when two Bears defenders failed to touch him. 

Dalton moved Chicago's offense from the start, but the Bears' opening drive ended with the first career interception for David Long Jr., who picked off a pass tipped by Kenny Young.

Los Angeles settled for two field goals in the first half, while Montgomery finally scored Chicago's first points 34 seconds before halftime.

Kupp put the Rams up 20-7 early in the third when Chicago's secondary left him completely unguarded 10 yards behind its safeties. Goff threw only two touchdown passes longer than 40 yards for Los Angeles all of last season.

Chicago kept it close with an 81-yard drive capped by Fields' TD run, but Darrell Henderson punched in another TD for the Rams late in the third after another smooth 75-yard drive. Woods then made a late 2-yard TD catch after a bit of impressive decision-making by Stafford.

Los Angeles scored at least 34 points only twice last season, making the playoffs largely with the NFL’s No. 1 defense.

House party

The Rams welcomed fans to owner Stan Kroenke's stadium during a festive evening that included appearances by former Rams stars Jackie Slater, Torry Holt, Orlando Pace, Jim Everett and Steven Jackson. OneRepublic played a halftime show.

Injury report

Bears: LT Jason Peters injured his quadriceps early in the third quarter of his Chicago debut. Rookie backup Larry Borom also came out later in the same drive with an ankle injury. ... Starting NT Eddie Goldman was inactive with knee and ankle injuries. Nickel back Duke Shelley also sat out.

Rams: Long left with cramps in the third quarter.

Up next

Bears: Home opener against the Cincinnati Bengals on Sunday. Dalton beat his old team with Dallas last season.

Rams: Road opener against the Indianapolis Colts on Sunday.