And it was truly a case of agony turning to ecstasy as they watched the side claw back from a 2-0 half-time deficit, keeping alive their hopes of progression to the knockout stages.
Cousins MK Pathan and Obaid Chaudhry were attempting to put a positive spin on matters as they watched Slovenia slamming two goals into the American net during the opening 45 minutes. Los Angeles native MK admitted: "We were expecting to win this game."
Obaid added: "I was on such a high on Thursday because my team, the LA Lakers, won the NBA basketball championship, so I thought things would go just as well today for the US."
With baseball, American football and basketball all drawing huge numbers of fans in the US, the country's soccer team is currently staking a claim for some headlines. Last week's opening-round game saw the Yanks snatching a surprise 1-1 draw against England. But the momentum had disappeared by yesterday afternoon, thanks to the efforts of a slick Slovenian side.
Kyle Wenninghoff from Nebraska explained: "Soccer's not as big as American football but we're still fans. We came in here hoping that they'd win!"
Seattle student Julia Pahlow, who has been studying in UCD for one month, remarked: "We had so many opportunities but failed to use them." Her classmate Billy Roggenkamp from California added: "It was awful in the first half."
Nonetheless, lady luck finally began to smile on USA when Landon Donovan found the back of the net just three minutes into the second half.
Regardless of the result, Crystal and Dustin Blodgett from Boca Raton in Florida had reason to celebrate as they are currently on honeymoon in Dublin.
Crystal explained: "We got married last Saturday and we've been here for two days. We're watching the match because Dustin is a soccer fan, but I'm just along for the ride".
While the couple will head to London for the next leg of their honeymoon, Crystal insisted they intend to tune in to Wednesday's clash against Algeria to keep in touch with USA's fortunes.
With the game ending in a 2-2 draw, a subdued atmosphere prevailed among fans who had been gearing up for a win.
But it didn't deter English fans Kim Slocombe, Liz Jones and Jen Gallacher, who had arrived in the Woolshed a full four hours early for last night's clash against Algeria.
The girls were celebrating their last day at work after a year as trainee managers in the Gresham hotel.
Kim revealed: "I'm a real football fan and during the last match I was working -- so I had to keep running out to Toddy's bar to keep an eye on the score!"