Portugal coach Fernando Santos wasn’t impressed by Cristiano Ronaldo’s reaction to being substituted off during their 2-1 defeat by South Korea – and it could lead to him being dropped for their last-16 game.

Ronaldo was replaced by Andre Silva in the 65th minute of the final group stage match on Friday, with the 37-year-old forward denying afterwards he swore at Santos for taking him off.

Portugal captain Ronaldo said his comments were actually made at a South Korean player who was telling him to hurry up in leaving the field. Regardless, Santos wasn’t pleased with Ronaldo’s reaction but insisted the issue has been resolved ahead of Portugal’s last-16 encounter with Switzerland on Tuesday.

“Let’s split this answer in two,” Santos said at his press briefing on Monday. “Right after the match, I spoke in the flash interview, and then went to the press conference, and there I said something I’ll repeat here: on the pitch, I didn’t hear anything.

“I was too far [away], and this is why I only saw him arguing with a South Korean player, and nothing else. Have I already watched the footage? Yes. I didn’t like it. Didn’t like it at all. From there, it’s things you sort out internally. It was sorted out this way, and now we think about the game tomorrow. Everyone is focused on the game,” he added.

On whether Ronaldo will start against Switzerland following the incident, Santos said, “I only tell the team who will play in the dressing room. When we’re in the stadium they find out about the team. And they know that. It’s been like this since I arrived. I will start the team that I think should play. It’s what I’ve been doing my entire life. I’m OK with myself, have no problem. I stay with my conscience.”

“Maybe after the match I reflect on it that I might have taken a different decision. But it’s been like this since I arrived in 2014. ‘I only think about what’s good for Portugal and the national team. And the [Ronaldo] topic is done, we sorted it out internally. It’s all sorted out.”

Portugal had already qualified for the knockout rounds ahead of Friday’s game and the scores were tied at 1-1 when Ronaldo was taken off. Portuguese media said the former Manchester United, Real Madrid and Juventus forward used vulgar language towards Santos as he left the field.

It was suggested Ronaldo also said something like: “He’s in a rush to sub me.”

But Ronaldo said after the game: ‘What happened was before my substitution, the South Korea player told me to get off quickly. I told him to shut up as he doesn’t have that authority.

“There was no disagreement [with Santos].”

After the match, which South Korea won thanks to a stoppage time goal by Hwang Hee-chan to book a last-16 date with Brazil, Santos corroborated Ronaldo’s version of events. However, it appears after watching back replays he changed his tune.

Ronaldo was forced to watch on from the bench as Portugal were defeated and he has still not been able to equal Eusebio’s national record of nine goals in World Cup finals.

• A Daily Mail report