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(CNN) -- Goalkeeper Tim Howard says the explosion of interest in soccer in the United States is "mind-blowing" off the back of Team USA's surprise progression from the World Cup "Group of Death" to the last 16.
Few gave the U.S. team much chance of finishing in the top two from the likes of Germany, Portugal and Ghana, but it has defied the pundits to reach the knockout stages.
Howard, who plays for Everton in the English Premier League, has been a key figure, making a string of fine saves to restrict group winners Germany to a 1-0 win Thursday.
It left Team USA tied on four points with Portugal, but qualifying for a match against Belgium next Tuesday because of a superior goal difference.
The 35-year-old veteran of 103 internationals had also been in top form as the U.S. tied Portugal 2-2 in its second group match, building on its 2-1 win over Ghana to start the tournament.
The huge support in Brazil, an estimated four times as many U.S. fans as followed England's under achieving team, plus unprecedented scenes across America with fans crowding to watch games on big screens, has come as something of a surprise to New Jersey-born Howard.
"The fact that it has really swept the nation is incredible for us as American players to see that," he told CNN.
"The interest has been mind-blowing and we've enjoyed watching every second of YouTube clips and Instagram and Twitter,"
"We've come so far in a short period of time. You know, the sport in our country really isn't that old," he added.
Howard also believes coach Jurgen Klinsmann has been vindicated for his selections after coming under fire before the start of the World Cup for leaving out fan favorite Landon Donovan and picking four German-born players in his squad.
"He's from day one made a lot of bold, powerful decisions. Some people call it cutthroat even," he said. "But he's strong in his decision making, and that's what a leader has to be. You can never waver."
Klinsmann said Friday he was "optimistic" striker Jozy Altidore will return from injury to play against Belgium after sustaining a hamstring injury in the win over Ghana.
Another key player, midfielder Jermaine Jones, has also been cleared to play despite breaking his nose in the narrow loss to Germany.
Howard believes they can provide another upset to beat Belgium, which won all of its three group matches, building on the momentum of earlier performances.
"We have a lot of other things we want to do, starting with Belgium, but you know we're proud of ourselves. We worked hard.
"It was the Group of Death, and people didn't give us a lot of a chance. We have to believe we can do it," he added.
Howard -- who spent four years with Manchester United before transferring to Everton -- has become something of a cult hero, sporting a thick black beard in direct contrast to his shaven head.
He had first grown it during the last EPL season and has changed his mind once or twice about its merits.
"It was my strength. I loved it, and then I cut it. I just cut it because I was tired of it.
"But I just decided to grow it back. There's never a rhyme or reason when I decide to grow it. It just happened."
Howard will be hoping it brings his side luck again when it faces Belgium, looking to reach the quarterfinals of a World Cup for the first time since 2002.