The Kansas City Chiefs cruised to a 45-10 win against the Detroit Lions in front of a sell-out crowd at Wembley.
The Chiefs scored 38 unanswered points on the way to recording their biggest win of the season despite falling behind on the opening play.
Quarterback Alex Smith threw two touchdown passes and went over with a rushing touchdown of his own.
The Chiefs equalled the New England Patriots for the most NFL points scored at Wembley.
The Patriots beat St Louis Rams 45-7 at Wembley in 2012.
This was the third and final instalment of NFL matches at Wembley in 2015. In the two previous games in October, the New York Jets beat the Miami Dolphins 27-14 and the Jacksonville Jaguars beat the Buffalo Bills 34-31.
The Lions now have just one win in eight games after making the play-offs last season, while the Chiefs have now put together back-to-back wins after losing five in a row.
Chiefs quarterback Smith said: "It was about putting four quarters together and we did that today. I was especially pleased with the second half when we stayed focused despite having a big lead.
"We had dug a little hole for ourselves earlier in the season, but the last two weeks have been good for us. We now have the second half of the season to look forward to."
Early lead proves a false dawn for Lions
The Lions arrived in London several days ahead of the Chiefs in a bid to get an edge, and it appeared to have paid off when Matt Prater kicked a 35-yard field goal on their opening drive.
The Chiefs responded immediately and De'Anthony Thomas set the tone for the rest of the afternoon when he went over for a 10-yard touchdown.
Smith had a field day in front of 83,624 fans, picking holes in the Lions defence and after a career-longest 49-yard run he followed up on the next play with a 12-yard touchdown.
Smith's opposite number, Matthew Stafford, then threw two interception passes, resulting in a Cairo Santos field goal and a Charcandrick West touchdown.
Trailing 24-3 at the break, the Lions needed an immediate response, but it was normal service resumed as Smith picked out Travis Kelce in the end zone to extend the Chiefs' lead.
The Chiefs were in no mood to ease off and Jeremy Maclin became the fifth Chiefs player to go over after missing last week's win against Pittsburgh with concussion.
Stafford offered the Lions some hope when he threw for Lance Moore to roll into the end zone for his third touchdown of the season, but Spencer Ware, with his first NFL touchdown, restored the Chiefs' 35-point cushion.