Gomez scored for the United States against the Czech Republic
England's first opponents in this summer's World Cup, the United States, lost 4-2 to the Czech Republic in a friendly in Connecticut.
Coach Bob Bradley, who is set to name a final 23-man squad for South Africa on Thursday, rested a number of his front-line players.
Despite taking the lead, Bradley's weakened team was undone by a Czech side that did not reach the World Cup.
England face the US in Rustenburg on 12 June in their first match in Group C.
Bradley has already stated his intention to name his final squad six days earlier than Fifa's 1 June deadline in order to "start the team-building process".
However, the display of his largely fringe side in front of 36,218 fans at Rentschler Field will have done little to make his task any easier.
"It's a night when you can only imagine the emotions players are going through but we're at a point where tough decisions have to be made," said Bradley.
"I have so many things flying through my head right now. I've already said live on TV that Gooch [Oguchi Onyewu] played 90 minutes when we subbed him in the 65th minute so you can imagine where I'm at.
"At times it was a little bit crazy and I think in the process of trying to put so much into it we at times left ourselves wide open."
Despite front-line players, including Everton goalkeeper Tim Howard and midfielders Landon Donovan, Michael Bradley and Fulham's Clint Dempsey, being rested and defenders Carlos Bocanegra and Jay DeMerit still recuperating from injuries, the US took the lead in the 17th minute when Rangers' Maurice Edu pounced on a loose ball to score from close range.
However, the Czechs turned the game on its head either side of half time when firstly Tomas Sivok headed them level before Jan Polak found space at the far post to fire them ahead just before the hour.
Seven minutes later, the US gave themselves hope of a positive result when Herculez Gomez headed in but a 78th-minute strike from Martin Fenin and Tomas Necid's injury-time turn and finish gave the Czech's the victory.
Bradley will take his 23-man squad to Philadelphia for Saturday's farewell home game against Turkey before the US travel to the World Cup.
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