Even Cristiano Ronaldo, stony-faced for most of a thunderous night, raised his hands above his heads and applauded.
He was saluting Jadon Sancho’s opening strike but he could have been acclaiming this entire United performance. Vibrant, direct, energetic, committed, robust, and not short of technical excellence that has been a stranger to this squad for some considerable time.
And Ronaldo, alongside Harry Maguire on the United bench before making a late cameo, could have been clapping Marcus Rashford for his welcome, long overdue return to proper football. Rashford had his best game for an age but he was not alone there - think Bruno Fernandes and Sancho. And there was a star turn from Lisandro Martinez who looked far more comfortable alongside Raphael Varane.
This was a transformed United but you have to admit they were catching their old rivals at an opportune moment, a midfield trio of James Milner, Jordan Henderson and Harvey Elliott looking a little ordinary by today’s elite standards.
And so it proved, Milner’s most eye-catching moment his tirade against Virgil van Dijk after the opening goal.
Mind you, any number of Liverpool players - including Milner himself - could have been given a rollocking at that point, although better to give due credit to Sancho for showing the class he has mainly kept under wraps since his move from Dortmund.
Nice control, nice feint to send a couple the wrong way and a calm finish. He was granted the freedom of Liverpool’s penalty area, true, but it was still a high-quality piece of play.
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And the breakthrough was not ill-deserved, Anthony Elanga having cracked one against a post after a fluent three-pass move.
United’s surprising vibrancy and directness unsettled Klop’’s side and Trent Alexander-Arnold, in particular. This was yet another exhibit in the case for him having no defence.
But as Liverpool eventually established a foothold in the game, Alexander-Arnold could concentrate on what he prefers to do but Liverpool were finding it tough to create clear chances, a miscued Fernandes clearance that hit the outstanding Martinez on the goal-line the closest they came to an equaliser before the break.
Predictably, Liverpool started the second half on the front foot but were always going to be vulnerable to United’s speedsters on the counter-attack.
And that was the scenario when substitute Anthony Martial freed Rashford and he clipped in a right-footer and then got the benefit of a tight VAR offside check.
But with well over half an hour left, there was time for Liverpool to respond and despite being unusually laboured, they eventually got one back when Mohamed Salah headed home after David de Gea had saved a Fabio Carvalho shot.
It set up a nervy finale for United but, by a variety of means, they managed to get through it unscathed and few would begrudge their new manager his first Premier League win.
Ten Hag made the big calls and was rewarded… and even Ronaldo might have to applaud him for that.