The World Cup co-hosts suffered a 5-2 defeat in a friendly international in Atlanta and face another stern test of their ability at the same venue on Tuesday when they go up against Portugal.
It was only the fifth time in four decades that the US has conceded five goals in a game, but Pochettino insisted it was better to lose heavily in a pre-World Cup warm-up game than once the tournament kicks off in June.
“I see this as a good check reality for us, because now is the moment to feel this type of situation, to improve. We need to improve, of course,” he told reporters.
“It’s only a game. It’s only a game where nothing went for us. I’m disappointed with the result, but seeing the performance, we cannot say the players didn’t perform.”
The US coach said it would be hard to convince fans there were positives to take from the loss but added: “To feel sometimes the pain is good.”
“I think there were many positive things and with all these types of results, it is better it is going to happen now."
The US did play without key defender Chris Richards and central midfielder Tyler Adams, who are both injured, and as a result lacked bite at times.
“We were not aggressive enough,” Pochettino added. "But the moment we matched the intensity of Belgium, we were even or better. The problem was to keep that intensity.”
The Americans did have chances and especially pivotal was a miss in front of goal from captain Christian Pulisic. After weaving his way into position with a sublime display of skill, he shanked his effort well wide with the goal at his mercy.
Belgium immediately went down the other end and took a 2-1 lead after the US had opened the scoring.
“It’s frustrating for me, it’s been a tough patch. But I feel confident in the way I’m playing,” Pulisic said.
He is likely to be one of the key players for the US, whose World Cup gets underway on June 12 against Paraguay in Los Angeles.
“I’m creating chances. So I just have to stay positive and keep going,” he said.
The Americans are co-hosting the World Cup, which runs from June 11-July 19, with Canada and Mexico.