"This one the referee owns," Kreis said after the loss.
Referee Matthew Foerster handed out seven cards in all four to Real Salt Lake in front of a sellout crowd watching what some had dubbed a possible MLS Cup preview.
"The level of consistency was as low as I've ever seen from any referee in MLS," Kreis said. "I don't want to belabor the point about him being poor. He is going to be poor. It's the fourteenth match of his entire career."
Kreis had expected a physical battle with Sporting.
"It's two teams that are winners," the RSL coach said. "Two teams that want to compete really badly and to win really, really badly, and I think we're fighting for respect."
It did not take long for that physical contest to bear fruit. Not even a full minute had ticked off the clock when RSL defender Chris Wingert collided with Sporting's Kei Kamara. As the Kansas City forward lay on the ground, Wingert was shown the game's first yellow card something that would prove all too costly for RSL later.
As the two teams battled, Kansas City's relentless pressure provided a number of chances for the visitors. But third-string goalkeeper Jeff Attinella, making his first MLS start with Nick Rimando gone and Josh Saunders injured, held his own for much of the contest.
In the 55th minute, RSL was the beneficiary of one of Foerster's calls. A tackle that took out Morales' legs gave Kansas City a yellow card and Real Salt Lake a free kick from 30 yards out. After Morales chipped the ball into the air, Kansas City keeper Jimmy Nielsen mistimed his jump, tapping the ball behind him, where Robbie Findley was there to head in the goal.
But when Wingert picked up his second yellow on a tackle in the 66th minute, the game changed.
Only seconds later, Kansas City took advantage with forward Soony Saad hitting home a Claudio Bieler pass for his third goal in his last two matches.
RSL collected itself after that and appeared ready to gut out a short-handed draw.
But when the referee allowed play to continue well after the five minutes of announced stoppage time had run out, SKC's Ike Opara found room past Attinella for the game winner.
"He looked calm. He looked ready," Kreis said in praise of his third-string keeper's effort. "I wish the ref was ready for it."
Storylines Sporting K.C. 2, RSL 1
R The loss ends RSL's 11-game unbeaten streak across all competitions.
• Referee Matthew Foerster hands out seven cards on the night, four to RSL.