Sir Alex Ferguson added three more refereeing decisions to a growing list of gripes in the aftermath of United's 2-1 defeat at Chelsea.
The manager criticised the call to punish Michael Carrick for handball in the 85th minute, given that Michael Essien's cross was destined to be cleared.
"Its a major decision thats cost us the game," Sir Alex rued. "To give a penalty for that in a game of such importance, on the linesmans say-so, is absolutely diabolical.
"Granted the ball hit his (Carrick's) hand but he couldnt get out of the road. He didnt lift his hands above his shoulders or above his head, and the ball was going straight to Rio Ferdinand anyway. The referee should have seen that.
"Earlier, when Ronaldo came on, he was grappled almost to the floor by (Michael) Ballack (at a United corner) and it was a clear penalty kick. And when Michael Carrick went down in the same way, the referee was right there but again he didn't give it. The game hinged on major decisions and unfortunately they didnt go our way."
Sir Alex cited several other examples from recent weeks when calls made by either the referee or his assistants have affected United's quest for domestic success.
"We were knocked out of the FA Cup after not getting a penalty kick," he recalled.
"We should have had a penalty from Mike Riley at Middlesbrough when their player dived and saved the ball. And the linesman we had today, Glenn Turner, flagged Wayne Rooney when he was through and five yards onside.
"This is a good moment for me but it is not just my award, my team-mates have helped me a lot this season. They give me good passes to score goals - and I score.''
Cristiano's remarkable tally of 38 goals so far this season include his first hat-trick for United - against Newcastle in January - and a run of eight strikes in seven consecutive games from 15 March to 13 April. The winger has also set up numerous goals for his team-mates as the Reds close in on a possible Premier League and Champions League double.
Ronaldo is only the second player to win the PFA award in two successive years since its inception in 1974. Ironically, he'll come face to face with the first man to do it on Tuesday when Thierry Henry (2003, 2004, then of Arsenal) lines up for Barcelona.
Cristiano wasn't the only Red to be heralded at the PFA awards - Rio Ferdinand and Nemanja Vidic were also named in the Premier League Team of the Year:
David James (Portsmouth); Bacary Sagna (Arsenal), Ferdinand, Vidic, Gael Clichy (Arsenal); Ronaldo, Steven Gerrard (Liverpool), Cesc Fabregas (Arsenal), Ashley Young (Aston Villa); Emmanuel Adebayor (Arsenal), Fernando Torres (Liverpool).
Fanzone Poll: If you could sign one player for United from the PFA Team of the Year, who would it be? Cast your vote at
www.manutd.com/polls.