If football was divided between "triers" and "flyers" then Juergen Klinsmann's uber-fit side would be an embodiment of the former, while World Player of the Year Cristiano Ronaldo could be considered the archetype of the latter.
For 14 minutes in the 30 degree heat and 65 percent humidity of the Amazon basin on Sunday, it looked like the triers would prevail courtesy of Clint Dempsey's goal, which he most unglamorously bundled over the line with his stomach.
But quality will often emerge and after 94 minutes of contributing very little, Ronaldo whipped in an inch perfect cross which substitute winger Silvestre Varela rocketed into the net with a diving header.
It was a brutal end to the evening for the Americans, who had poured heart, sweat and soul into their quest for a second victory and a place in the last 16 for the fourth time in the last seven tournaments.
Klinsmann has come under repeated flak for over-training his players, a criticism which gained more currency when his key striker Jozy Altidore limped out of the World Cup with a hamstring strain in the opening 2-1 victory over Ghana.
Central defender Matt Besler was withdrawn from the same match in Natal after feeling his own hamstring tightening, although he was fit to start on Sunday.
Klinsmann's pre-tournament boot camp was vindicated in sultry Manaus, however, when his team made light of the stifling heat and battled back after handing the Portuguese a fifth minute lead through a Geoff Cameron defensive error.
Nani snapped up that chance with alacrity and nearly scored again with a thumping shot that came back off the post in stoppage time in the first half with Tim Howard saving brilliantly to deny Eder from the rebound.
Those moments apart, the Americans had contained the Portuguese and Jermaine Jones, the rock at the heart of the United States midfield, equalised by a curling the ball into the net with a strike of no small quality in the 64th minute.
Whether or not he has a debilitating knee injury, Ronaldo, as he had in the 4-0 defeat by Germany with which Portugal opened their campaign, looked distinctly out of sorts until his decisive contribution at the end.
The 2-2 draw means the Americans need only a point from their final match against Germany to guarantee their progress from one of the toughest groups at the World Cup.
"The US are known to give everything in every single game," said Klinsmann.
"We have that fighting spirit and determination to try to win every game and therefore we will go for a win against Germany."
Portugal find themselves with their destiny out of their own hands as they prepare for their final group match against Ghana.
Coach Paolo Bento was left bemoaning the impact on his squad of so many having played for European clubs competing for silverware.
"Many of the players had a very short break before the World Cup and we have hence had many injuries during the tournament," he said. "This will of course limit our options."