Agar was baffled by Robert Hicks’ award of a try to Josh Charnley which levelled the scores early in the second half.
The Warrington winger appeared to put the ball down on defender Brad Dwyer’s arm or chest, but Hicks backed up referee Chris Kendall’s original ruling of ‘try’.
“It is a real shame one of the deciding factors has been a try given by the video ref that clearly wasn’t a try, nowhere near a try,” Agar insisted.
“You just wonder what they are looking at.”
Agar added: “I can’t see, in all the replays we saw, any evidence that ball touched the floor.
“I know it went up as a try but there’s certainly evidence to suggest - from every single angle - that ball absolutely didn’t get down, nowhere near.
“How on earth he has come up with a try, I am not real sure.
“I feel sorry for our guys to have to put up with decisions like that.”
Even so, Leeds led by six points going into the final five minutes, only for Warrington to equalis with a converted try before England half-back George Williams, on his debut, booted the winning drop goal with just 38 seconds left.
Agar stressed: “The way we managed the last five minutes really hurt us.
“I thought for the bulk of it, our effort and a lot of the things we did were really good, we just didn’t make Warrington work hard enough for their tries in the first half.”