The US National Team was seen breaking down to obvious joy, and maybe tears after their physically exhausting victory against the tough Ghana team. Coupled with the heat and humidity of Natal in Brazil, the feat was otherwise taxing that coach Jurgen Klinsmann gave his team a day-off with no practice session ahead of its next match against Portugal, Yahoo Sports said.

The sports blog said the US' next match against Portugal would be more grueling than Ghana, for several reasons. The match, which is scheduled for Sunday, will be held in the remote heart of the Amazon rainforest, Manaus. The stadium in the area, which is just 214 miles south of the equator, had earned condemnation from both Italy and England, who first played in the stadium.

Italian star Claudio Marchisio said after defeating England 2-1, "At times it felt like [I was] having hallucinations due to the heat."

Yahoo Sports said that the temperature during the England-Italy match was at 86 degrees, with humidity upping the heat index to 91.

Sunday's forecast by weather.com revealed that the temperatures in Manaus would be along similar levels, with 85% humidity. The US National Weather Service said with temperature levels like this, expect a heat index of 99.

Both Italy and England along with international players' union FIFPro had been calling for FIFA to have cooling timeouts to guard against physical risks of intense temperatures.

Another challenge Klinsmann would need to solve before Sunday was the absence of striker Jozy Altidore, who was left with a strained left hamstring after the team's win against Ghana, US Soccer Federation spokesperson confirmed. Clint Dempsey, on the other hand, will be playing despite suffering a broken nose during its match against Ghana, TIME said.

On the other hand, one bright spot for Team USA would be Portugal star player Cristiano Ronaldo's knee injury. Although Ronaldo has been confirmed to play on Sunday, the reigning FIFA World Player of the Year might drop out of this year's tournament entirely, if reports are to believe, due to a career-threatening patellar tendon injury in his left knee.