Landon Donovan, shown here playing for the L.A. Galaxy last month, will lead the U.S. national soccer team in a friendly against Spain on Saturday and against Canada in a Gold Cup match on Tuesday. (Elsa/GETTY IMAGES)

Over the next four days, the U.S. national soccer team will play Spain and Canada, opponents offering a vast gulf in quality and pregame fervor.

Spain captivated the planet last year in South Africa, playing with elegance and class in winning its first World Cup. With a roster featuring artistic geniuses from FC Barcelona and Real Madrid, La Roja has retained soccer’s top ranking and forged a deserved place in the annals of the modern game.

Canada hasn’t qualified for a World Cup in a generation, sits between Estonia and Latvia at No. 76 in the FIFA rankings, and hasn’t beaten the United States since Landon Donovan was 3 years old (1985).

In the Americans’ eyes, one game stands appreciably taller than the other — and it’s not the affair with Spain.

While Saturday afternoon’s encounter with the world champions might sell out Gillette Stadium in suburban Boston and attract global attention, it’s merely a friendly and, beyond national pride and confidence-boosting qualities, doesn’t carry long-term consequences.

Conversely, the Canada match Tuesday in Detroit serves as the U.S. opener in the CONCACAF Gold Cup, a 12-nation tournament for the North and Central America and Caribbean region that rewards the winner with a trip to the 2013 Confederations Cup in Brazil – a major tuneup for the World Cup a year later.

“The Spain game is a fantastic opportunity, but we have to keep an eye on the big picture,” captain Carlos Bocanegra said. “The Gold Cup is the prize for the summer.”

Which isn’t to say the Americans are treating this like a sleepy match against Norway involving secondary players. Far from it. Coach Bob Bradley has recalled almost all his primary charges from the European leagues and, with a big crowd and a national TV audience observing, the Americans are relishing the chance to upend the world’s best.

“As a competitor, you want to play in this game,” said Donovan, who scored against the Spanish in the 2009 Confederations Cup semifinals, a 2-0 stunner that ended Spain’s 35-game unbeaten streak. “You want to acquit yourself well. We’ll be smart about it, but we’re not here to be the nicest of hosts.”

Because this match falls so close to the Gold Cup opener, Bradley will use the maximum six substitutes and limit the amount of time his key players spend on the field.

In explaining how he will manage the roster, Bradley said: “It’s a little bit like doing Sudoku where we keep putting certain things down, and then in the end, there are two ‘9s’ in the same line so we have to start over.

“It’s important that we play well. There are things we want to work on, but at the same time, make decisions that will fit the Gold Cup.”

In other words, the outcome is secondary to the health and welfare of his players and how effectively they perform in difficult situations. Although Spain’s possession game, keyed by World Cup hero Andres Iniesta, is authoritative and mesmerizing, “I think we’ll have bits and pieces of the game,” U.S. goalkeeper Tim Howard said.

Donovan has been rounding into form with the Los Angeles Galaxy and midfielder Clint Dempsey, with 12 league goals for Fulham, is coming off one of the best campaigns ever by an American playing overseas. While leaning on veterans, Bradley could also turn to one-time prodigy Freddy Adu, 22, who has returned to the national team after a two-year absence, and Juan Agudelo, 18, who scored against Argentina in March.

Although all of his players are recovering from long club campaigns, Spain Coach Vicente del Bosque isn’t messing around. He invited 17 from the World Cup squad, including six from the Barcelona side that overwhelmed Manchester United in the Champions League final last Saturday in London.

Eleven of the 23 players are from bitter rivals Barcelona and Real Madrid. Notable absences include Xavi Hernandez, Iniesta’s Barcelona dance partner in central midfield; Spain captain Carles Puyol (knee surgery); and Arsenal midfielder Cesc Fabregas.

The World Cup title hasn’t erased the memory of the loss to the United States two years ago. “It was a lesson for all of us,” Real Madrid midfielder Xabi Alonso said. “Hopefully it won’t repeat itself.”

And while the Americans admit to having the Gold Cup in the back of their minds, they relish the opportunity to play a world titan.

“You can never play enough big games,” Howard said. “You win some, you lose some, but to play in the biggest games on the biggest stage, let’s face it, it’s a full house and the best team in the world.”

U.S. notes: Natural grass has been installed over Gillette Stadium’s artificial turf. . . . By late Friday afternoon, more than 61,500 tickets had been sold. . . . Midfielder Benny Feilhaber (ankle) is sidelined.