Through more than 80 minutes on a cool, drizzly night, the visitors were in a familiar position. They were ahead in the game 1-0, having stymied the Timbers' attack and taken the lead courtesy of a fluke goal from Benny Feilhaber.
But then, with time draining away, the Timbers — who hadn't scored against Kansas City at home in nearly three-and-a-half years — turned the evening on its head.
An equalizing goal created by Diego Chara and finished by Jeremy Ebobisse set the stage for a slumping Brian Fernandez, who woke up on Saturday morning with a stomach virus and was held out of the starting lineup as a result, to bang home the winner in stoppage time.
Pandemonium ensued. Fernandez's headed goal, which came with 94 minutes on the clock, ties Andrew Jean-Baptiste's famous winner against the LA Galaxy in 2013 as the latest Timbers game-winner in Providence Park MLS history.
Like that goal, the images from this one — Fernandez dropkicking the ball high into the night and leaping to embrace Diego Valeri in midair, green shirts sprinting towards them, drums being swung over heads behind them in the stands — are going to last.
It was a rapturous ending to a trying evening, a cathartic breakthrough for a struggling Timbers' attack, and a moment of North End magic that in an instant reshaped the Western Conference playoff race and likely finished Sporting Kansas City's season.
Had they won this game, Peter Vermes' team would have drawn themselves level with Portland on 40 points and set them up to make a last-gasp push for their ninth consecutive postseason birth. Instead, they walked off the field six points adrift of the red line, in need of a miracle and then some to extend their season.
Given the age of their core, a full rebuild may be around the corner in Kansas City. If that's the route Vermes takes in the offseason, it will spell the end of an era — and the end of one of MLS's best and quietest rivalries.
Kansas City and the Timbers produced some excellent shows over the last number of years, and even with both sides significantly shorthanded due to various international call-ups and injuries, this one didn't disappoint.
Fittingly, as with most of the great games between these teams, Saturday night's was a slow burn.
With only 14 field players available, Sebastian Blanco having injured himself in training to add to the raft of expected absences, Giovani Savarese rolled his team out in a 4-3-3 — with Diego Valeri playing as a false nine in between target wingers in Jeremy Ebobisse and Dairon Asprilla.
At the very beginning of the game, it looked like the tactical wrinkle might pay dividends. The Timbers moved the ball with purpose and interchanged early and often, dominating possession and putting Kansas City on their heels.
Jorge Moreira forced a fingertip save out of Tim Melia after just a handful of minutes, and the Timbers were briefly awarded a penalty by referee Alex Chilowicz before he reversed his call with the aid of video review, but after riding out the initial storm, Sporting began to settle into the game.
All three were willing runners, but it was Gerso who was most inventive — and his deflected shot ten minutes before halftime that clipped the far post was as close as either team got to opening the scoring before halftime.
The pace picked up in the second half, but 20 minutes into the period, it was the strangest of goals that broke the deadlock when Feilhaber, deep on the left side of the field, cut to the outside and arched what must have been a cross over a backpedaling Steve Clark's right shoulder and into the upper side netting.
The veteran midfielder put both hands to his face in a show of mock embarrassment. Had he tried to shoot, he could never in a hundred attempts have spun the ball as perfectly or precisely as he'd just accidentally done.
Not a minute later, Feilhaber would go down injured as he tried to shield the ball from his old enemy Chara and was substituted. But his work, at 34 years of age, was done: Sporting had the lead, and with it another injection of energy and belief.
The Timbers, now, were seriously up against it. They nearly found a game-tying goal with 20 minutes to play when Claude Dielna flashed across the face of goal to flick a Valeri corner on, but his header caromed off the far post.
Savarese threw on Fernandez and Marvin Loría, but it looked like it might just be another one of those nights against the Melia-Matt Besler-Graham Zusi axis in Kansas City's defense.
But, this time, the Timbers flipped the script. With ten minutes left, Chara found Loría and then surged forward. The Costa Rican found him, Chara fired a ball across that took the slightest of touches off of Kansas City center back Graham Smith, and Ebobisse was free on the back post to stick it in.
The crowd, and their team, was back in it. As the match moved into its final stretch, the stadium pulsated with tension — the sky dark, the field wet, both sides a shade or more desperate. It felt like a playoff game.
And it got a commensurate conclusion. In the 95th minute, Tomás Conechny brought down a header from Smith and played Valeri, who had flared out to the righthand side. As Smith went to cover him, the Maestro twisted inside and out, and lifted a tantalizing cross that stranded Melia in the middle of the goal.
As Sporting's goalkeeper turned and watched, Fernandez came crashing through on the back post to head it into the back of the net.
Fernandez let out a blood-curdling scream as he charged towards Valeri, the two tackling each other to the ground and quickly finding themselves enveloped by a scrum of Timbers players.
When he finally rose from the soaking turf, Valeri gave the crowd a fist pump. In another season of indelible moments from the Argentine, this stands out: a stupendous cross, conjured out of thin air, to break Fernandez's duck and win a critical game.
Several kicks of the ball later, it was over. To say that the Timbers needed this victory, after scoring just two goals and losing twice in their last three home matches, would be a dramatic understatement. They had to have it — and somehow, thanks to a bucketload of grit and a late dose of sublime skill, they delivered it.
Should these three points launch the Timbers into another late-season charge, it will matter all the more. But whatever happens from here, for the collection of players who kept believing on Saturday night, this will remain one to remember.
Portland 2, Kansas City 1. A fightback for the ages, against a team that has always been worth beating. There will be few sweeter results.