Portugal exited Euro 2024 last Friday, losing 5-3 on penalties against France in the competition's quarter-finals.

The last time Liam Scales faced-off against Portugal, captained by 39-year-old Cristiano Ronaldo, the stakes were much lower. But the intensity of the workout was comparable.

In a pre-Euros friendly between Ireland and the Roberto Martinez-led national side, Celtic's 25-year-old centre-half was put through his paces at the Estádio Municipal de Aveiro where Portugal ran out 3-0 winners.

Despite having tested himself against some of Europe's best in the UEFA Champions League last campaign, the Irishman admitted he and his teammates' opponents on the night were a class above.

"At Ronaldo’s first goal, another player would have taken that shot and I would have blocked it because my foot was there," said Scales. "But he looks for perfection and puts it right into the top corner, out of my reach and the keeper’s reach.

"Next time I play against quality like that, I will know that you can’t even give them that tiny margin. You have to be almost perfect against them. Ronaldo’s movement in the box is up there with the best ever.

"For his second goal against us, the ball came in from our right and he has sprinted towards goal, so I have dropped into the six-yard box. He has then stopped dead and that has created space for the player to find him with a cutback.

"For a left-footed first-time finish, it was quality. But it was the movement before it that stood out. The split-second, start-stop double movements were unbelievable.

"He is the best I have ever played against movement wise and he was always looking to threaten off your shoulder too. It was a nightmare to deal with it."

Read more: 

In-line with the characteristics showcased during the 2023/24 Scottish Premiership trail, Scales promised to use his brush with greatness – one of world football's best-ever players, no less – as a learning experience.

Celtic now stare down the re-formatted UEFA Champions League, where they'll play eight games against eight different opponents in a fixture schedule that will run into the new year by default.

Scales added: "That experience has definitely made me hungrier and it’s shown I need to work harder. I went into that game thinking it would be a good challenge, but it was a level above what I have played against before. So it showed me that there are levels to go up.

"I think I will be better placed to play against these guys having had that experience. It comes down to the fine margins when you face players of that level."