Miles Starforth's match analysis: Oxford United 3 Newcastle United 0

And Benitez named a Newcastle United side that was ill-equipped to beat a League One club.

Oxford United were given all the encouragement they needed when Benitez handed in his teamsheet at the Kassam Stadium.

It was a side that lacked fitness and sharpness.

Curtis Good hadn’t played a game for the club in almost three and a half years.

Others had hardly kicked ball for Newcastle this season.

Benitez said he wouldn’t take any “risks” with his key players in the build-up to the game. He didn’t. And his team was deservedly beaten 3-0 on a forgettable afternoon in Oxfordshire.

But Newcastle’s manager took a huge FA Cup risk with his team. And he knew it. He was comfortable with that risk given the importance of promotion this season.

Benitez will be judged on one thing, and one thing alone, this season.

And that’s the club’s finishing position in the Championship.

The FA Cup? That can wait for another season, in Benitez’s view. It’s an understandable view, though the 1,787 fans that travelled to the Kassam Stadium, rightly, expected more from their team.

Benitez’s squad, arguably the best in the division, has been weakened by injuries and the African Cup of Nations.

Jonjo Shelvey – who could have made all the difference – watched the game from the bench.

Shelvey had a hand in all three goals in Newcastle’s 3-1 win over Birmingham City in the last round of the competition.

The midfielder was named as a substitute, but there was little chance of Shelvey making it on to the pitch.

A subdued Benitez was philosophical after the game in the Kassam Stadium’s packed media room.

“I said that if we go through, we will do it with the squad,” he said.

“If we cannot, we cannot. Obviously, I feel sorry for the fans, and also for us because we wanted to go through. We could have done it in the first half. Now, we have to analyse why we made the mistakes and be ready for the next game.”

Benitez was right. Newcastle did create chances.

Most of them fell to a half-fit Aleksandar Mitrovic, who was back from the gashed leg he suffered in the club’s third-round tie at St Andrew’s.

Mitrovic forced two saves from Oxford goalkeeper Simon Eastwood in the first half. He slipped before he was able to take another opportunity.

The home side had had the better start on a poor pitch, but Newcastle ended the half well.

Oxford took the lead after the break – Kane Hemmings scrambled the ball over the line from a poorly defended corner in the 47th minute – and it went from bad to worse from that moment on.

Mitrovic won a penalty – he was dragged down by Phil Edwards after making a driving run into the box – but goalkeeper Simon Eastwood got to his low spot kick.

The save energised Oxford’s players and fans.

It gave them belief that they could go on and win the game. And they did, comfortably.

A powerful header from an unmarked Curtis Nelson put Michael Appleton’s side 2-0 up. And Newcastle conceded a third goal from a corner late in the game.

Toni Martinez, on his debut, headed past Sels, who was helpless. Again, he was unmarked.

Newcastle, with a three-man defence led by stand-in captain Grant Hanley, were awful defensively.

They just couldn’t defend balls into the box. Had Jamaal Lascelles or Ciaran Clark been on the field, they would surely have dealt with those corners better.

“We did our homework and were analysing almost everything,” added Benitez.

“In the end, football is a game where you have to take your chances. We had our chances and we didn’t take them.”

At the final whistle, Newcastle’s players, including club captain Jamaal Lascelles, went to the away end, which had started emptying after Oxford’s second goal.

They were apologetic. They knew they should have done better, much better.

This could prove to be a defining few days for the club’s Championship campaign.

First, there’s the transfer deadline on Tuesday night. Then there are two home games.

Benitez wants at least one signing, though he knows there are no guarantees that a new player will arrive this week.

Newcastle, it seems, are reluctant to spend in the transfer window, despite having made a £30million-plus profit last summer.

Owner Mike Ashley seemingly feels he has already given the best manager in the division the best squad in the league.

But no team can stand still, even in the Championship.

Benitez has made a strong case for additions to a squad which, for all the money spent on it last summer, still has weaknesses.

There isn’t an understudy for Shelvey, for one. If Shelvey suffered injury, or picked up another suspension, Newcastle would be vulnerable.

That’s why he wasn’t risked on the Kassam Stadium’s bobbly and bumpy pitch.

Discussions are ongoing. Benitez has refused to talk about his interest in Andros Townsend, but he would love the winger back at St James’s Park.

Townsend could all but guarantee promotion. He’d also be an asset next season.

So why not spend? A potential deal involving Chancel Mbemba going on loan to Crystal Palace has been mentioned.

That could work, as Benitez is relatively well-covered in defence and Mbemba isn’t a player who is suited to the demands of the Championship.

Newcastle simply can’t afford stand still this month, even if that means spending some of the millions it banked in the last transfer window.