Portuguese Soccer teams

SAO PAULO, Brazil — In the wee hours Tuesday morning, as the U.S. national soccer team’s charter traced the Atlantic coast in returning to base from its World Cup opener up north, the coaching staff’s attention pivoted to Portugal.

And pivoting to Portugal meant pivoting to superstar Cristiano Ronaldo.

Since FIFA conducted the group draw in December, dropping the Americans into the same quartet as the planet’s premier performer, Coach Jurgen Klinsmann and his assistants have done the groundwork — scouting, studying and plotting for Sunday’s match at Arena da Amazonia in Manaus .

Now they must implement the plan. If done effectively, the Americans could secure passage to the round of 16 for the second consecutive World Cup.

Klinsmann will not reveal his tactics until Argentine referee Nestor Pitana sounds the opening whistle, but the nature of soccer suggests a collective effort involving both attacking and defensive elements to suppress a player of Ronaldo’s mercurial skills.

“You’ve got to be on high alert when he touches the ball, ” midfielder Kyle Beckerman said, “because he’s just so dangerous.”

The Real Madrid winger scored 51 goals in 47 matches across all competitions in 2013-14, ending Lionel Messi’s four-year reign as world player of the year. Ronaldo has posted 252 goals in 246 appearances since joining the Spanish titans in 2009 — the primary reason he is, according to Forbes magazine, the world’s second highest-compensated athlete at more than $80 million ($52 million in pre-tax salary, $28 million in global endorsements).

On Friday, though, teammate Helder Postiga told reporters at the team’s training base near Sao Paulo that “he’s training with us, he’s practicing with us and he’s doing all the exercises. I’m not a doctor, but I don’t think [Ronaldo’s playing status] is in question. He has been training at his maximum.”

The Americans have not lowered their guard despite Portugal being in a wounded state from the defeat, defender Pepe’s red-card suspension and injuries to several other starters.