The Gamba Osaka players react after their red card to Ronaldo for a foul on Lionel Messi.
The goal was not a penalty and was ruled as a yellow card.
“He should be banned for life,” said Kakyo Matsumoto, who scored the opener.
“We all knew it was a red card.
We knew it would be a yellow one but we were expecting a penalty.”
Sergio Romero, who made his debut against Udinese, said: “I was disappointed but I’m satisfied with the way the game was played.”
Ronaldo was shown a yellow in the 68th minute when he was shown two yellow cards for dissent.
His next red card was shown in the 89th minute for a challenge on Paulo Henrique and his next yellow for dissent came in the 87th minute on Carlos Tevez.
The Portugal international was also sent off in the 82nd minute when a tackle on Gonzalo Castro in the box was assessed as a foul.
The referee decided to send him off for a second yellow.
“It was difficult, but we’ll go from there,” he said.
“I’m really disappointed.”
The penalty came as a huge blow to the team that finished second in the table with four points from three matches.
“This is a huge result for us and it’s not going to stop us,” Matsumotos said.
Ronaldo was also handed a second red card in the 90th minute after a challenge by Javier Rodriguez, who was sent off for an unsportsmanlike conduct charge.
“Ronaldo is a big target for all the opponents, especially with this team,” Sergio Romero said.
“They can only take it away from him.”
The match was not going as planned.
The first half started with a 1-0 lead, but things started to go wrong in the second half.
Ronaldo scored in the 58th minute from a penalty that was awarded after the goalkeeper failed to react to the challenge of Gonzalo Perez.
Gamba scored twice in the opening minutes of the second period, both from free kicks that bounced in off the crossbar.
Ronaldo had two shots on target, one of which was saved by Cristiano Ronaldo.