In two games, Minnesota United's proficiency at executing set pieces has ranged, in coach Adrian Heath's estimation, from "really dangerous" to "awful," a disparity that has its extenuating circumstances.

In Sunday's 1-0 home victory over D.C. United, Loons midfielder Jan Gregus wasn't the only one who struggled with the pace and positioning on his free kicks.

Even D.C. United great Wayne Rooney couldn't find the proper footing on Allianz Field's newly grown grass in what otherwise is one of soccer's most threatening game situations.

"The fact Wayne Rooney's were bad as well gives you an idea that it wasn't easy on the foot," Heath said.

The game before, Rooney scored a winning free kick at Columbus. He has four free-kick goals since joining D.C. last summer. No one else in MLS has scored more than one such goal in that time.

The ability to bend the ball on corner kicks, or around a wall of defenders from dead-ball situations, is a reason the Loons used their third designated-player slot to acquire Gregus last winter.

United star Darwin Quintero's inconsistency on free kicks made Gregus the team's designated specialist, until he drew a red card at Toronto two weeks ago and was suspended for the next game.

Quintero assumed that role on set pieces for the ensuing match, a scoreless draw with the L.A. Galaxy. He delivered a couple of corner kicks into the box that defender Ike Opara just missed converting into scoring headers.

"We just need to be better all around," Opara said. "At times, the runs have been there and the service hasn't been. And sometimes the service has been there and the runs haven't been."

Heath called Quintero's delivery on corner kicks "really good" in the Galaxy game.

"He has been inconsistent in the past," Heath said. "That's why we put Jan on them originally."

On Sunday, Gregus got four of six corner kicks past the first defender. The other two he played short in the corners of a field that has been spongy to start the season.

"What can I say? It wasn't good,'' Gregus said. "I can say it was the surface. But no, I'm not going to use that excuse. Luckily, we scored not from set pieces."

United, with 51 corner kicks in its first 10 games, is among the league's top third in attempts. But it hasn't scored on a set piece yet.

One day, Heath suggested the 6-3 Gregus also can be a "big help" in the box. On another, he sounded certain Gregus is best serving the ball.

"I don't think heading is one of the strongest points of his game," Heath said.

Gregus and Quintero provide different looks. Gregus puts more pace on his free kicks, Quintero aims to place the ball in specific areas.

"We have many options," Gregus said. "I can serve it. He can serve it. We can play short."

Gregus took every Loons' corner kick on Sunday, when Quintero played just 51 minutes because of an injured ankle.

Heath was asked if deciding who takes free kicks is game-planned or comes in the heat of the moment.

"With Darwin, it's heat of the moment, Heath said. "With the rest, it's planning. He goes on instinct and sometimes you have to go with that."

Jerry Zgoda covers the Minnesota United for the Star Tribune. jzgoda@startribune.com