Atlanta's high-octane offense pressured, possessed, yet struggled finding the back of the net.
So United kept attacking until it paid off.
Josef Martinez scored in the 67th minute to help expansion United beat the Colorado Rapids 1-0 in front of 44,938 fans at Bobby Dodd Stadium.
Atlanta (7-7-3) has won four straight at home after dropping two of its first three.
The highest-scoring team in the MLS struggled to get good looks in the first half. It came out firing in the second.
"They put you under a ton of pressure," Rapids goalkeeper Tim Howard said. "(A lot of) attacking power and they proved to be worth it tonight. They make it tough to get out, they press you well and they take care of the ball."
Atlanta started the second half with eight shots, all by Martinez and Miguel Almiron. Three of Martinez's seven shots were on target, both season highs.
Despite Atlanta's attack, Howard was an imposing presence in the net, making six saves.
In the 65th minute he made a diving one-handed save on Martinez's bicycle attempt.
"That is why he is the U.S. national team goalkeeper," Martinez said. "He made some big saves tonight. Luckily, I was able to convert one of my chances and that's why the three points stayed at home tonight."
Martinez beat with a left-footed shot off a cross from Brandon Vasquez for his seventh goal in seven appearances this season. He started after coming off the bench in three games since returning from a thigh injury. The assist was Vasquez's first of the season.
Alex Kann made two saves for his second shutout of the season for Atlanta.
But early on, Colorado had a couple near-goals.
The Rapids (5-10-1) narrowly missed back-to-back chances, first, when Dillon Serna's long-distance shot hit the crossbar, then Joshua Gatt missed consecutive looks on an open breakaway.
Colorado made a mounted effort to equalize in the waning moments.
Alan Gordon's attempt was blocked in the 89th minute. Justt before the final whistle, Kann fell on Bismark Boateng's shot off of a corner kick.
"Everyone was going to challenge for the ball and I was just trying to get myself between the ball and the goal," Kann said. "Thankfully, he headed it towards me, I got my body behind it, and got the rebound. It hit my forearms and then I got on top of it."
Martino credited a growing home-field advantage as a contributor. The venue has sold out every game this season.
"The team feeds off that energy," Martino said about the sold-out stadium. "I think there's a really good communion between the fan base and the team so we're able to take advantage of that energy."
Coming off a home loss to Los Angeles on Wednesday night, the Rapids — last in the Western Conference standings — are winless on the road.
