With attacking midfielder Darlington Nagbe also drafted in, as well as goalkeeper Jesse Gonzalez, the American squad has a more familiar look to it from the experimental line-ups that faced Panama, Martinique and Nicaragua in the group stage.
The U.S. may have posted its second consecutive shutout in the tournament, but almost gave up an early opener in the third minute when Lichaj played a poor back-pass that Rodolfo Zelaya pounced on.
The 12-team Gold Cup tournament has reached the quarter final stage with three power nations of the CONCACAF region - Costa Rica, Mexico and the United States - all avoiding each other in the first round of knock-out games.
Canadian referee Drew Fischer, a Major League Soccer regular, did not penalize the incident, which occurred in the 57th minute.
With the crisis averted, the US rebounded well and appeared to strike first in the 17th minute, as Gyasi Zardes broke free into the left side of the box unmarked and placed a shot past the keeper into the net.
There was plenty of rolling around and playing for fouls, as well, which contributed to the USA looking frustrated and out of sync.
As if being bit and having his nipple twisted by El Salvador defender Henry Romero wasn't enough, US striker Jozy Altidore now may also be in trouble at home. Altidore had been kicked and tripped and fouled all game and given his strength, that's nothing new.
"They are games you want to win", forward Jozy Altidore said Tuesday after training at Rhodes Field at the University of Pennsylvania.
Dempsey may be slowing down, and he certainly doesn't play any defense or apply pressure to ball handlers, but holy hell does he still pop up with game-changing moments of magic.
It wasn't seen on camera but Altidore wasn't the only one who experienced a bit of teeth in his flesh.
"But like I said, you just have to move on as quick as possible and look onto the next [game]".
Midfielder Darwin Ceren is the lone El Salvador player who plays in Major League Soccer. "I was just laying there until the guys came over".
"It's different, following from afar and then jumping in like this", Altidore said.
"I thought we had a hard time tonight", Arena said after the match. "Our timing wasn't good".
The first, consisting of three USA national soccer team matches in a lightweight group, would spotlight nearly everyone on a mostly novice, mostly MLS roster: blossoming prospects, players seeking second chances and those forgotten under the previous coaching regime.
"I started running and I realized 'I'm really exhausted here". "I needed that goal because I wasn't having the best of games".
United States of America - semi-finalists in 2015 - had two unlikely players to thank, defenders Omar Gonzalez and Eric Lichaj, for the quarter-final victory in Philadelphia on Thursday (AEST). Jamaica faces Canada while Mexico play Honduras. Arena started 22 players in three group-stage matches, the USA going 2-0-1 to win Group B in form that was rarely convincing.