Everything is different now for the United States men's national team.
When this World Cup started, the Americans were upwards of a 15-to-one long shot to survive Group G. Another World Cup, another "Group of Death" for the Americans and a probable quick exit for Klinsmann's men were all recurring media themes in the run-up to the tournament.
Then John Brooks' 86th-minute header shocked Ghana after Germany had earlier eviscerated Portugal by a 4-0 count that no one could have predicted.
And now the Americans are no longer Group G's sorry prey. Far from it, the Americans should be aggressive and brazen hunters for as long as their tournament life lasts.
Gone is the idea that the Americans should play for three draws, or count on Germany to win their first two matches and then go easy on fellow countryman Klinsmann next week.
With three points in hand, the United States now has a remarkable, unthinkable chance to beat Portugal, all but ending their tournament and, per Nate Silver of FiveThirtyEight, to very nearly punch their own ticket to the knockout stage.
Silver's analysis of the probabilities states that if the Americans draw with the Portuguese and go on to lose (as expected) to Germany, the Americans are "favored to advance, but not safe."
That is why Klinsmann must resist the understandable urge to play for one point against Portugal. The Americans should put all of their chips in the center of the table against a diminished Portuguese side and play to win.
Which is how you could end up with striker Chris Wondolowski in the starting XI in the injured Jozy Altidore's place. Aron Johannsson replaced Altidore in the second half against Ghana and is another possibility, but Wondolowski has X-factor ability.
If Klinsmann is content to play for a point, he will probably change the Americans' formation by replacing Altidore with another midfielder (Mix Diskerud or Graham Zusi, most likely) in hopes of strangling Portugal through the center of the pitch.
What a huge waste and a real disappointment such tactics from Klinsmann would be.
Just as a reminder, this Portugal side was outclassed and whitewashed by Germany. In the process, Portuguese defender Pepe was sent off with a red card for elbowing, then head-butting Thomas Muller. Pepe is therefore out against the United States.
Remarkably, that might not be the worst news the Portuguese received after their throttling by the Germans.
Cristiano Ronaldo is dealing with a knee injury that, depending on who you believe, is nothing or is virtually everything to the reigning Ballon D'Or winner.
The Daily Mail's Richard Arrowsmith reported recently that "Cristiano Ronaldo was warned by his doctor that he risks threatening his career by playing on for Portugal at the World Cup."
That sounds hyperbolic, but as Arrowsmith continues, the cold truth of that assertion becomes easier to accept.
"Ronaldo was pictured limping out of training with his knee heavily strapped. There had been serious doubts over the Real Madrid superstar's fitness ahead of the tournament, after a thigh problem and tendonitis in his knee forced him to miss training and two warm-up matches," Arrowsmith asserted.
Think seriously about this situation for a moment.
Will the Americans ever be presented with a chance like this in a World Cup match again? A situation where one of their opponent's two best players is disqualified from play and the other is physically unable to play his best? This sort of luck just does not come around much.
So Klinsmann needs to play with the same smash-and-grab offensive-minded formation that produced a first-minute goal and a late match-winner against Ghana. And since Landon Donovan is not on this roster and Altidore is beyond unlikely to be ready for Portugal, Wondolowski will have to do.
If that sounds like damning Wondolowski with faint praise, well, um, sorry.
What should Klinsmann do in Altidore's absence?
The San Jose Earthquakes man had a great opportunity to distinguish himself in the Americans' San Francisco friendly against Azerbaijan last month, only to have at least two legitimate scoring chances go begging.
Even a healthy Altidore would never have made the Americans favorites over Portugal, and as of this writing the Portuguese are better than an even-money choice to win per Oddsshark.com. Almost certainly those odds reflect the belief that wounded Portugal will play desperate football having already lost their first match.
How did that work out for Spain? Exactly.
The Americans should try to jump on Portugal the same way they seized early control over Ghana, and then they should keep trying to score until Portugal, like Spain, crumbles.
So Wondolowski should start and Klinsmann should go for the kill.
When will Klinsmann ever get such a chance again?