Atlanta United’s extraordinary opening chapter came to the ideal conclusion for hometown fans on Saturday night, as an MLS record 73,019 crowd saw them defeat Portland 2-0 to win MLS Cup, in only their second year of existence.

Josef Martinez eased any local memories of infamous Atlanta sporting collapses with a typical poacher’s goal just before half-time, and then with a keen but limited Portland team pushing for a comeback, Franco Escobar finished off a 54th minute set piece at the back post, to tilt the mood in the stadium into decidedly celebratory mode.

With coach Tata Martino leaving to take the Mexico job, and inspirational playmaker Miguel Almiron parlaying his own extraordinary tenure in MLS into a likely move to the Premier League, the coming off-season was always likely to represent an inflection point for an Atlanta project that has steamrollered into the league as both a competitive and cultural force.

At times, even as they have dominated opponents with their high-speed attack, and racked up more points than any other team playing during their short history, that competitive aspect has almost been taken for granted amid the focus on the sheer spectacle of the Atlanta United phenomenon. But make no mistake, in a town without a major sporting championship since 1995, it mattered that the end of the beginning came with a win.

Yet this was also an extraordinary spectacle for the league. Grateful MLS executives may wonder what they have done to deserve this. The last time Portland Timbers appeared in an MLS Cup final, in 2015, they won the title in front of 21,747 fans in Columbus. Now the Timbers found themselves competing in front of a crowd larger than any of the last four Super Bowls, in a state of the art stadium, against a team who didn’t exist three short years ago.

Atlanta fans are not shy about reminding the rest of the league about the benchmarks they have set. Before the game kicked off, a giant tifo banner of a steam train was hoisted in the main supporters’ section. Barreling at full speed, it was emblazoned with the legend “MLS 3.0”.

Presumably we were to imagine this train rumbling over flattened timbers, and in truth, the Timbers could do little to derail Atlanta, on a night when their usual plan of well-drilled containment and countering looked inadequate.

Brad Guzan celebrates as Atlanta’s victory is confirmed. Photograph: Jason Getz/USA Today Sports

Both teams started cautiously, befitting the stakes of a final, and Portland perhaps saw a little more of the ball than they may have anticipated early in the game. But Atlanta were the clear aggressors, pushing their overlapping wide players forward trying to pull Portland out of shape, and not shy about sending long balls over the top to test the honesty of Larrys Mabiala and Liam Ridgewell at the heart of the Portland defense.

Still, clear chances were at a premium for both sides, until Atlanta forced a breakthrough from nothing in the 39th minute. Michael Parkhust, the Atlanta captain had lost all four MLS Cups he had played in – the last one in Portland’s 2015 win over his Columbus Crew SC team. Now he had the decisive touch in bringing the Cup to Atlanta. With Portland trying to play the ball out of the back in risky fashion, Parkhurst pounced on a loose touch from Jeremy Ebobisse. His lunging tackle touched the ball towards Josef Martinez on the edge of the box. The Venezuelan’s quick touch and thought left a flailing Ridgewell stranded, before Martinez neatly stepped around Jeff Attinella to place the ball into an empty net.

Portland have made something of a habit of second-half comebacks in this playoff run, not least when Sebastian Blanco’s gut punch of a golazo turned around the Western Conference final. For a brief flash in the early moments of the second half they looked like they might be about to play themselves into this game as well, but then Almiron’s free kick was flicked on by Martinez to meet Escobar’s sprint to the back post, and when the defender placed the ball across Attinella for 2-0, the result rarely looked in doubt.

Portland kept working, but their attacks increasingly looked like backdrops for the curtain calls Atlanta’s stars were taking as the minutes ran down. Man of the match Martinez was subbed out for Hector Villalba in the 86th minute, to an ovation that was perhaps only exceeded by the one for Almiron, in the 90th minute.

It looks likely to be the last minute Almiron plays as an Atlanta player – bigger stages await. Though on the evidence of tonight, not much bigger.