On May 14, the Union won there, 2-1. Last year, while still in the playoff hunt, the Union kept their hopes alive by winning, 1-0, in Kansas City on Sept. 27.
"That is one of the toughest places to play," Curtin said. "We have grinded out a couple of results there and dodged a lot of bullets."
Curtin said the Union were relatively healthy, although midfielder Cristian Maidana, who has a team-high eight assists, remained bothered by a hamstring injury.
"He is a possibility, but he is not 100 percent," Curtin said.
Recently the offense has clicked, but the defense has not had the same consistency.
The Union are 2-1-2 since Curtin took over for John Hackworth and have outscored teams by 11-8 in MLS games during that span.
The combination of Sebastien Le Toux and Conor Casey has combined for 14 goals, with Le Toux having a team-high eight.
Overall this season the Union are tied for first in the Eastern Conference with 33 goals, but they also have allowed the third most in the 10-team conference, 35.
The Union have not played a game in MLS since a 1-1 draw at Chicago on July 19. Their most recent outing was a 1-0 loss Friday to visiting Crystal Palace of the English Premier League in a friendly.
The Union will face a shorthanded K.C. defense. U.S. national team member Matt Besler won't play because he received a red card in Saturday's 2-1 win at Toronto. Keeper Eric Kronberg is out with a fractured left hand.
On a local note, Kansas City manager Peter Vermes, of Delran High and Rutgers University, will be among three people inducted into the team's Hall of Honor at halftime.
Union at Sporting Kansas City
What: Major League Soccer, Union (5-8-8, 23 points) at Sporting Kansas City (11-5-5, 38 points).
When/where: Friday, 8 p.m.; Sporting Park, Kansas City, Kan.
TV: NBC Sports Network.
Union on the road: 3-6-3; K.C. at home: 4-1-5.
Goals for: Union, 33; K.C., 31
Goals against: Union, 35; K.C., 19.
Last MLS game: The Union played the host Chicago Fire to a 1-1 draw July 19; K.C. earned a 2-1 win on Saturday at Toronto. - Marc Narducci