Omar Gonzalez heads home the U.S.’s first goal. (Bill Streicher/USA TODAY Sports)

PHIADELPHIA — For the eighth consecutive CONCACAF Gold Cup, the United States has booked a spot in the semifinals.

The Americans rode first-half goals from defenders Omar Gonzalez and Eric Lichaj to register a 2-0 quarterfinal victory over Panama in front of 31,615 at Lincoln Financial Field.

The U.S. will play in its 13th semifinal as it will face Costa Rica at AT&T Stadium in Arlington, Texas Saturday at 10 p.m. ET.

The victory also extended the USA’s unbeaten run to 12 matches (7-0-5) since Bruce Arena returned as head coach, setting a team-record unbeaten streak at the start of a U.S. MNT coaching tenure.

Still, Arena was not happy with the team’s overall performance.

“I thought we had a difficult time tonight,” he said. “Our timing wasn’t good, we didn’t do well with the physicality. The game had no rhythm with all the fouls, and players falling on the ground.

“But we weren’t good on top of it. It took us 30 minutes to play a little bit. Then we got a little bit more assertive, and took up good positions on the field, and capitalized on a couple of their mistakes.

“But it was just a sloppy game overall.”

After an early scare that saw goalkeeper Tim Howard come off his line to deny Rodolfo Zelaya’s breakaway in the third minute, the USA had a golden opportunity four minutes later when Clint Dempsey’s effort inside the box was smothered by former St. John’s University goalkeeper Derby Carillo.

The U.S. tried to jump ahead 10 minutes later when Dempsey fed Gyasi Zardes inside the left side of the box and he buried his effort past Carrillo, but despite appearing even at the time Dempsey played the ball, Zardes was judged to be in an offside position.

The Americans tallied two goals before the break. The first score came in the 41st minute when Michael Bradley’s free kick from the left flank found Gonzalez, who nodded the ball past Carrillo’s outstretched arms to record his second goal in as many matches.

The advantage doubled in the second minute of first-half stoppage time. A build-up through midfield led to Justin Morrow finding Dempsey, who took the ball on the turn before finding Lichaj, the right back, in full stride entering the area. Lichaj took one touch before burying his first international goal through Carrillo’s legs.

Arena said that Lichaj was a “good defender, no question about it. He still needs a little bit more experience at this level, but he fits in well with the team.

“That’s a position we need help. DeAndre Yedlin was injured for a fair amount last year. We didn’t have him for all of our games. It’s nice to know that Eric is a player that perhaps we can depend on to help us in that position.”

El Salvador remained dangerous in the second half, but saw most of its attempts off frame of the goal.

Dempsey had another decent chance to increase the lead to three, but saw Carrillo make a diving stop on his 75th-minute attempt.

Front Row Soccer editor Michael Lewis has covered 13 World Cups (eight men, five women), seven Olympics and 25 MLS Cups. He has written about New York City FC, New York Cosmos, the New York Red Bulls and both U.S. national teams for Newsday and has penned a soccer history column for the Guardian.com. Lewis, who has been honored by the Press Club of Long Island and National Soccer Coaches Association of America, is the former editor of BigAppleSoccer.com. He has written seven books about the beautiful game and has published ALIVE AND KICKING The incredible but true story of the Rochester Lancers. It is available at Amazon.com.