Even given the scoreline, there were positives - and Jacob Murphy was chief among them
With Christian Atsu ruled out with a thigh-muscle injury, Benitez had a huge decision to make as to who was going to start wide on the left.
A significant proportion of fans wanted to see Rolando Aarons given the nod, despite the fact he had not played a single minute of Premier League football this season before this weekend, but instead it was Murphy who started at Old Trafford - despite having appeared short of confidence in recent weeks.
Given that he was the most-expensive signing of the summer at £10million, however, Benitez is keen to integrate a player who he firmly believes has bags of potential and will eventually have a big future at Newcastle.
His first contribution of note in this game was to give the ball away after five minutes when the visitors had launched a promising counter attack.
But, from then on, he grew in confidence - and showed exactly why Benitez believes he has immense promise.
Full of pace and trickery, Murphy unsettled Ashley Young and Martial down the Man United left, helping lead a number of first-half counter attacks.
His run and curling effort which forced a flying save from David de Gea during the second half also showed how his direct style could be effective in the top flight.
One area in which the 22-year-old must improve is his decision-making, with the winger shooting on occasion when he should have passed - and perhaps that is one of the reasons we have seen so little of him in black and white so far.
This was his most-encouraging display to date though, and hopefully it provides him with a welcome confidence boost.
This very correspondent wrote a fortnight ago that he would be surprised to see Benitez regularly opt to field a 4-4-2 formation again in the Premier League, particularly on the road.
Yet, in the very next fixture and at one of the most daunting away grounds, Benitez did exactly that.
Dwight Gayle and Joselu both retained their places in the side - but this was not a conventional 4-4-2 formation.