Brock Purdy led the San Francisco 49ers to an upset 27-7 win over their rival Los Angeles Rams, as Melbourne turned it on for the historic first NFL regular-season clash Down Under.
A massive crowd of 100,021 fans packed a sold-out MCG on Friday, with Australia's largest stadium bathed in brilliant spring sunshine throughout the contest.
It was the second-highest international attendance in NFL history and the league's seventh-biggest regular-season crowd of all-time.
Thousands more filled venues across the road at Melbourne Park for the NFL Kickoff Festival.
The Rams were the nominal 'home' team but San Francisco were heavily favoured in the stands, and 49ers quarterback Purdy starred in the fierce NFC West rivals' season opener.
Purdy completed 25 of 34 passes for 205 yards and three touchdowns, while wide receiver Mike Evans caught six passes for 49 yards and one touchdown.
The 49ers spent a full week in Melbourne to acclimatise in the build-up, and the move appeared to pay dividends.
"We've had a lot of really good wins together, but this was a special experience," San Francisco head coach Kyle Shanahan said.
"Having to come this far ... it took a couple of days to kind of get our minds right, but it felt like home once we got there.
"The guys played like that today."
In stark contrast, the Rams' planned hit-and-run mission fell flat in an early-season horror show.
They arrived just 28 hours before kick-off and attempted to keep their body clocks on California time.
But head coach Sean McVay conceded just about everything went wrong for the Rams in a "humbling" experience, as quarterback Matthew Stafford threw one interception and completed 15 of 25 passes for 155 yards.
"Today was one of those days and I make no excuses," McVay said.
"Whether you want to say it's about travel or whatever, we just weren't good enough in that window.
"I didn't coach good enough and we'll look at it and move forward."
Eddy Pinerio kicked a 20-yard field goal to give San Francisco the first NFL points on Australian soil before Stafford's 41-yard pass to Puka Nacua got LA in position late in the first quarter.
Kyren Williams finished off the drive with a five-yard run into the end zone on the first play of the second quarter, giving the Rams a 7-3 lead.
But the Niners were up 10-7 at halftime after Purdy connected on a deep strike, finding Demarcus Robinson for a 39-yard touchdown.
The Jonas Brothers made a brief appearance at the main break and San Francisco's advantage grew to 17-7 early in the third quarter with Purdy's two-yard pass to Evans.
In a pivotal moment, the 49ers' defence held firm when they stopped Stafford's attempted sneak from the one-yard line on fourth down.
Purdy cashed in when he steered a 99-yard drive, putting the Niners out of reach when he scrambled to throw a 15-yard pass to Deebo Samuel.
Fans flooded the MCG and Yarra Park precinct hours before kick-off despite the unusual 10.35am start time, set so the game could be broadcast in prime time in the United States.
NFL commissioner Roger Goodell wasn't surprised by the huge turnout, telling Netflix's broadcast that he's "never met a culture that loves sports more than this".
"We always had a high expectation that this would be successful. This exceeded it in every way," Goodell said.
"Think about this: We're on Friday at 10.30 in the morning and 100,000 people are going to be in a stadium watching an NFL game.
"That speaks volumes about the passion of these fans."
The NFL's first regular-season game in Australia is expected to pump $300 million into the Victorian economy.
At least one more game will be played in Melbourne under the existing four-year agreement, while the fight amongst other states for a slice of the action will ramp up after the successful first edition.
The Rams-49ers clash was the first of a record nine international NFL games to be played this season.
