With 58 seconds remaining in the game and down by four points, the Panthers threw caution to the wind with the game on the line. A sweeping backline movement appeared to be enough for them to seal a last-gasp victory but it was judged by video referees Steve Chiddy and Ben Galea to have been aided by an Adam Docker obstruction on Cronulla vice-captain Graham.
Cleary made his feelings clear post-match.
"All I'll really say on that, and I've been saying this for over a year now, is I think that we need to be able to adjudicate on whether a player has made a legitimate attempt ... to make tackles," Cleary said.
"We don't want diving in the game. I don't think it's that hard to work out – having said that we didn't play well enough to win the game."
While Penrith had chances to earn their first back-to-back wins of the season, Cleary lamented that his side simply weren't good enough.
"We weren't good enough in attack and defence," he said.
"We were way off from what we would normally produce and our energy was down. Maybe it was the five-day turnaround, if that's the case then your execution is going to come off worse. It was a flat performance today."
Penrith co-captain Kevin Kingston added: "We didn't take any of our opportunities, through all our dropped ball and poor defence, we still had a chance to win the game and we didn't do it."