Did he know something? Had he seen something in their lauded performances against New Zealand and Australia in the autumn which the experts had missed?
While the backs were dancing their brilliant patterns did the wily Kiwi notice a weak link up front?
Whatever the truth, what is unquestionable was that his side, shorn of some of its biggest stars, delivered a hammer blow to the Scots’ Six Nations ambitions and now has everyone re-evaluating the Welsh title challenge.
The scoreline in Cardiff of 34-7 did not lie. It could have been a lot more as Wales left at least two tries out there – and both of them would have been classics.
Scotland came to Cardiff as the ‘darlings of European rugby’, if you believe England coach Eddie Jones. They left with their tail between their legs and reassessing their prospects for a tournament which many had expected to be their breakthrough.
So what happened in Cardiff?
Everything Gatland expected, if you believe the New Zealander after a match which marked his decade in charge of Wales.
It was also his 50th win as Wales coach and the country’s 50th in the Six Nations.
He felt even before the game that the result was not in doubt.
“It was an afternoon I was expecting,” he said.
“The way that we’ve trained there was definitely a quiet confidence in the squad. The guys have been outstanding in their preparation and we did go into the game expecting to win and to win reasonably comfortably.
“I said that to the chief executive [WRU chief Martyn Phillips] yesterday in training – I thought we’d win by 20 because that’s how well we trained.”
Lucky breaks – or making your own luck
The flying start which saw Wales 14-0 ahead in 12 minutes was the result of two momentum-changing incidents.
Firstly Gareth Davies displayed predatory instincts to intercept Ali Price’s laboured pass and ran-in from 70 metres.
Then Price was pinged for a crooked feed at a defensive scrum (after Wales knocked on with a potential try of the season beckoning).
From that platform Leigh Halfpenny scored Wales’ second try and Scotland were playing a game of catch-up that never looked like producing much.
Halfpenny ‘the best in the world’
The Scarlets full-back had a day to remember.
After queries about his attacking abilities from full-back and a try famine going back to 2013, he crossed twice – once in either half. And he nailed all six of his kicks at goal.
Halfpenny’s haul of 24 points was his best in a Test match and impressed his coach.
“To me he is the best defensive full-back in the world,” Gatland said.
“His positional play and the way he does things and his work-rate is absolutely phenomenal when you look at the stats.
“So it’s pleasing to see him get some confidence from an attacking perspective.”
That Wales recorded such an emphatic win without 12 injured players – eight of them British and Irish Lions – was the main reason so many were shaking their heads in mild disbelief at the end.
“We haven’t spoken at all about the injuries and the players being unavailable,” a bullish Gatland said.
“I said to the players there’s no excuses this week, and the players that have come in all believe in their own ability.
“All of them believe they are better than the players who have been involved.
“I felt the way they’ve prepared was brilliant and our focus has been on developing that depth for the 2019 World Cup.”
Players coming in and impressing in the absence of others means inevitably, that Gatland will have a few issues to ponder when he picks his side to face defending champions England.
Wales have won at Twickenham three times under his management, but have not tasted success there since the 2015 World Cup.
Lions full-back Liam Williams is back in full training from Monday and North – having played 80 minutes for Northampton on Friday – is also back in the frame.
Hallam Amos, who shone on the wing in the autumn, is also available while Taulupe Faletau and Dan Biggar might need another game off.
Who does Gatland drop, if anyone?
“There’s going to be some tough decisions and it’s nice to be having that competition in the squad and having some quality players know they are having to fight really hard for their position,” was his summary.
England will be tough – much harder than the challenge the Scots presented in Cardiff, especially in the forwards.
Gatland knows that, but couldn’t help himself.
“We’ve got a bonus point win and go next week to a venue where we’ve had a lot of success in the last 10 years,” he added.
“I’m looking forward to it.”