The NFC West team were a class above their opponents at Wembley Stadium, with Kupp playing an instrumental role in their victory.
The wide receiver had seven catches for 220 yards and a touchdown as the Rams improved to 5-3.
As for the Bengals, they are now 0-8 and the No.1 pick in the 2020 draft looks like a genuine possibility.
Kupp's big day began on the Rams' opening possession.
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Jared Goff moved Los Angeles into the redzone with an impressive drive that included 21-and 25-yard throws to Kupp.
One positive for the Bengals this season has been their redzone defense, though, and they were able to limit LA to a field goal.
On the third play of the drive, Rams receiver Brandin Cooks took a helmet-to-helmet and was ruled out of the game through concussion.
Cooks has a history of concussions. He suffered one while playing for the New England Patriots in Super Bowl LII, and also had one in Week 5 of this season.
Cincinnati responded with a field goal of their own, with long receptions from Tyler Eifert and Tyler Boyd putting the Bengals in a position to tie the game at 3-3.
Cincinnati have little to play for this season but they arrived in London ready to match the Rams.
Cooks’ concussion increased Goff’s dependance on Kupp and the third-year pro had gains of 32 and 23 yards on the Rams’ next possession.
LA were suddenly in Bengals territory and scored the game’s first touchdown after Goff floated a pretty pass to Josh Reynolds for a 31-yard score.
Reynolds, Cooks’ replacement, ran past his coverage and Goff found him down the seam for six points.
Would the Bengals roll over and take their eighth-consecutive defeat? No.
Andy Dalton pieced together a superb drive and found running back Joe Mixon for a 1-yard score.
10-10. Interesting. The Bengals were hanging with last season’s NFC Super Bowl representative.
But the Rams have an offensive genius in Sean McVay as their head coach and they re-established a seven-point lead in style.
The Rams ran a double-reverse pass back to Goff which completely fooled the Bengals defence.
Goff found a wide-open Kupp and, after Bengals cornerback B.W. Webb slipped, the Rams receiver took it all the way to the house.
Kupp’s numbers with 3:15 remaining in the second quarter read: five targets, five receptions, 165 receiving yards, one touchdown. His fantasy owners will be over the moon.
The Rams led 17-10 at half-time. There could be no doubt about the effort that the Bengals were putting in, but a lack of playmakers on both sides of the ball was hurting them.
What they couldn't allow was a Los Angeles touchdown on the first series of the second half. But that's exactly what happened.
Goff found Kupp - who else? - for a 40-yard gain before Todd Gurley found the endzone with a three-yard rush.
That was to be the only score of the second half as the game finished 24-10 to the Rams. It was a successful trip to London for McVay's squad.News Now - Sport News