Atlanta United got its wake-up call.

It came four minutes into the season.

After squandering a couple early attacks, the Houston Dynamo went on the offensive. They attacked down the right side. Alberth Elis passed to Andrew Wegner who was in front of the goal and tapped it in. Just like that Atlanta United was playing from behind.

Their defense, already startled, continued to get pounded. Counter attacks seemed effortless for Houston. Set piece goals were too easy. Philippe Senderos received a long cross and scored on the header that went whizzing by Brad Guzan for the second goal. More trouble as Franco Escober couldn't clear the ball and it deflected right at Mauro Manotas who scorched the ball into the back of the net. Darwin Ceren capped the scoring in the first half by knocking in a ball that Guzan couldn't handle with little assistance from the back line.

All of Houston's goals were scored before halftime. Atlanta United dropped its first match 4-0, the worst loss in the program's short existence.

"Everything went wrong because we played terribly," captain Michael Parkhurst said after the match. Parkhurst entered as a substitute near halftime after Leandro González Pirez left the game with a hip contusion. "This is a great wake up call for us. We can't listen to the noise out there. We know that people like our team and think highly of us. That means nothing in this league until you go out there and prove it."

It's true. After last year's record start and big offseason moves, even casual soccer fans understand that Atlanta United has a talented squad destined for a deep run in the postseason.

But that's more than a half year away, and there's work to be done.

The offense struggled to maintain possession, had poorly executed crosses and lacked chemistry. Even Miguel Almiron and Josef Martinez, who combined for 28 goals last season, were not on the same page, missing goal-scoring opportunities.

"I think they just played to our lack of attacking ability," Greg Garza said on why they were outplayed.

Atlanta's starting 11 was tweaked two days before their season opener because of Ezequiel Barco's quad injury. He will be out 4-6 weeks. It forced Almiron over to the left and Julian Gressell to start in the center. Parkhurst started on the bench even though he said he is healthy.

Garza said the scheme changed two days before Saturday's match.

"We weren’t able to train that way the entire preseason. That was definitely a big blow for us to not only lose [Barco] but to try a new formation," he said. "You could definitely tell that on the field."

Manager Tata Martino wasn't calling out any names after his team's poor performance.

"I think today it was difficult for us to defend. It was difficult for us to recover the ball back and also defending one-on-one situations. I think offensively we created about the same number of chances as Houston did, but Houston was just able to take advantage. And when I talk about the team defense, I’m talking about the whole team. Everyone," Martino said.

Atlanta United has a week to make corrections. They return home and face D.C. United at Mercedes-Benz Stadium on Sunday. They'll see former midfielder Yamil Asad back at the pitch, this time on the opposing side.

But after the initial handshakes and slaps on the back, the Five Stripes will be more concerned about chasing after that first win and avoiding an early letdown.

"I think it’s a very competitive league," Martino said. "There are a lot of good teams, and we’re going to have to do our best to match what we did last season."