"Donovan is not out of it yet. He is 30 years old. He is one of the great players that the United States has produced. He is important for us," said Gomez. "But he is not the whole United States (team); that is like saying that Chicharito Hernandez is Mexico. We will be 11 against 11."
Gomez made his comments prior to Wednesday's United States-Mexico friendly (ESPN2, coverage beginning at 4:30 p.m.). The forward, who sees action with Santos in the Mexican league, is a seven-year MLS veteran who made his U.S. national team debut in 2007.
Donovan, meanwhile, said it will be a challenge for the U.S. team to beat Mexico on its home turf.
"Very good. They're very good," the L.A. Galaxy captain said. "They're a well-oiled machine. They know exactly what they're doing, they have a style that they like to play, and when they play at home, they're relentless.
"So, in my opinion, especially when they play here, they're one of the best teams in the world, no question."
Gomez said the timing of the match was a little rough for him, given the timing.
"I am a little tired. This will be my fifth game in two weeks with Santos, but I am excited to play," he said.
"Mexico is enjoying a great moment in soccer, but who knows who will be having the best day," said Gomez.
Last week, El Tri defeated Brazil 2-1 for the Olympic gold medal. Mexico is the reigning U-17 World Cup champion and its U-20 team finished third at last year's World Cup.
Gomez said he expects the 100,000 fans in Estadio Azteca to be cheering for Mexico. He said the animosity between the players on the two teams was "notable."
"Mexico is now doing very well," he said. "It came back with an impressive youthful team, but this moment is important because we don't want to fall behind."
The U.S. didn't even qualify for London, failing to get past the group stage in the qualifying tournament it hosted. The U-20s failed to qualify for the last World Cup as well.
It now has been more than three years since the Americans defeated Mexico 2-0 in the World Cup qualifier in Columbus, Ohio. The U.S. is 0-3-1 since then, including last year's 4-2 defeat in the Gold Cup final.
U.S. midfielder DaMarcus Beasley said Mexico is the team to beat right now.
"They're on the rise at the moment. They're a nation to look at and see what they're doing right. They've been doing well over the past 5 or 6 years with their youth development and it's paying off for them," he said.
U.S. national team coach Jurgen Klinsmann admitted that Mexico's dominance of Brazil at the Olympics demonstrates the teams' strength at this moment.
"There is a gap," he said. "[We'd be] foolish not to recognize that. If your team doesn't qualify for the Olympics and the other team wins the Olympics, there is a gap. On the senior national team level, they've done tremendously well over the last two years, too, so you've got to give them compliments for that."