The United manager said: "It was ridiculous. It was a penalty. I do not mind the referee getting the decision wrong but to book him was too easy an option.
"But he couldn't get there to book him quick enough. Is that because it was Ronaldo? Yes, absolutely."
Yesterday's triumph allowed the Old Trafford outfit to pick up their second piece of silverware, having won the Club World Cup, and Ronaldo believes United are on course to win five major trophies this season.
United already sit top of the Premier League, are in the last 16 of the Champions League and the quarter-finals of the FA Cup.
"At Manchester there is always an opportunity to win everything but we need to keep our feet on the ground," said Ronaldo.
"It's quite difficult and we have to think game to game. We won this cup and we are top of the League and in the Champions League and FA Cup. "It's always special to win. Manchester always want to win games and finals."
United claimed the trophy at Wembley after converting all four of their spot-kicks, with Spurs scoring only one of their three as Jamie O'Hara's effort was saved and David Bentley shot wide.
