"When you chill out a bit, you turn back into a spectator," said the Bournemouth and Scotland midfielder.

"Watching Messi [scoring a hat-trick against Algeria] and stuff like that, it's incredible to watch that happen. It's immense and pretty surreal, to be honest.

"When I was younger, I idolised Messi, so to think you're playing on the same kind of stage as him now is pretty cool, especially the age he's at. Watching him do his thing was unbelievable."

Tuesday was moving day in America, to an extent. A treble for Messi and doubles for Kylian Mbappe and Erling Haaland - the big boys came out to play. The tournament seemed to find another gear in the process.

For Christie, there was never any thought in his young head that he would ever make it to a stage like this. "Non-existent," he said. "I don't know if it sounds bad to say that.

"I had aspirations of playing for Scotland when I was growing up - that was my pinnacle - but you didn't ever think further than that. I never, ever envisioned playing at a Euros, never mind the World Cup.

"I didn't watch Scotland in a major tournament, so in my head that just wasn't really a possibility at that point - and probably why, all those years down the line, when we had that night in Serbia [qualifying for the first Euros under Steve Clarke] it hit home so much."

Christie, famously and endearingly, became very emotional in the aftermath of that victory. "[The tears] were because it felt so out of reach for me and a few of the other boys," he said.

"So, to be doing this here is incredible. Everybody has that feeling that you're playing on a stage that literally all the eyes across the globe are watching you. You're just desperate to try and make a name for yourself."

Following a cameo appearance off the bench against Haiti, the chance to make his mark could come from the start against the highly-dangerous Morocco in Boston on Friday (2300 BST).

Scotland are considerable underdogs, which is fair enough. But every underdog can have their day and Christie's team have it within them to prove sticky opponents for Morocco.

He takes confidence, he said, from the fact that Scotland have gone toe-to-toe with "teams that are as good as Morocco" in recent years. At 31, he's no wide-eyed innocent. He's not naive, he knows how brutally hard this is going to be against Morocco. He knows that Scotland will not dominate possession or limit Morocco to zero chances.

"We need to keep those numbers as low as possible and then do our bit when we do get the chance to hurt them," he explained.

Christie also believes Scotland can make it hard for Morocco to break them down. Asked if he truly thinks that his boys can win, he replied: "Absolutely. I think we've got to think like that. Especially after the first result against Haiti.

"We're trying not to get too ahead of ourselves, but at the same time, you've got to draw confidence from that and ride the wave a little bit."

Christie has just signed a new deal with Bournemouth and will remain at the club until 2029. He is, as they say, in a good place. Messi's exploits at 38 - he will be 39 this month - offers Christie a world of encouragement that this World Cup doesn't necessarily have to be his last.

In England, he sees players getting better with age, guys in their mid-30s who are still operating well at the top level. "Some are pushing for the high-30s and still churning out unbelievable performances week in, week out," he said.

Head coach Clarke has spoken often about the dynamic of starters and finishers, the importance of having influential players coming off the bench late on. That was the scenario Christie found himself in against Haiti. Tense moments, those.

Would he rather be a starter or a finisher? "I honestly don't mind," he commented. "I'm not too sure, to be honest. The manager's been very, very big on that, especially since we've come into the camp.

"He's making everybody realise that every single person in our squad is going to be needed at some point, whether some boys play three, four, five minutes, some players might play every minute, but everybody's got a massive part to play. Everybody's taking that on and doing their bit so far."

So to Boston for Morocco on Friday. One point and Scotland are more or less guaranteed a place in the knockouts. One stellar 90-minute performance, however challenging, and they're history makers.

"It's a dream come true to even play in a World Cup, but you have to quickly adjust your targets and adjust your mindset," added Christie. "From being happy to be here you want to go and create more and keep pushing the bar. The manager has kept the foot to the floor."

Having achieved one dream by making it to America, Christie is now pursuing another. Morocco await - the greatest test of his football life.