The old chestnut about Manchester United and their vulnerable midfield grows ever more relevant. Going down 4-1 to Manchester City might have been marginally more acceptable to David Moyes and the supporters if his side had made the 166th derby a contest.

The truth of the hiding that Wayne Rooney and company took at the Etihad Stadium is that from the start until interest wavered following Samir Nasri's goal to put City 4-0 ahead after 50 minutes, the home team punched holes through the champions at will.

As the post-mortem starts, there may be despair at the paucity of options Moyes has to freshen up a midfield that was steamrollered by Yaya Touré in particular. Shinji Kagawa, Anderson, Tom Cleverley, Ryan Giggs and, possibly, Phil Jones all come with various caveats that make this a puzzle that should have been solved before the transfer window closed.

The drubbing handed out by Manuel Pellegrini's fast and muscular band is seen as a final confirmation of the summer folly of purchasing only Marouane Fellaini, who was left appearing off the pace and possessing questionable positional sense, which is hardly what £27.5m should buy.

The drab 0-0 draw with Chelsea at Old Trafford, the 1-0 defeat at Liverpool and now the humiliation at City mean that against two title contenders and a top-four pretender United have managed only a point, illustrating why Moyes wanted to recruit Cesc Fábregas from Barcelona.

The opening of the great void at United's centre can be traced back to Roy Keane's departure in 2005, with Owen Hargreaves's infirmity (summer 2008) and the need for Paul Scholes to come out of retirement (January 2011) staging posts in what is a perennial topic for fans.

Hargreaves and Scholes are name-checked because since Keane left they were the two prime candidates identified by Sir Alex Ferguson for the role of midfield linchpin that had also been occupied with distinction by Bryan Robson, Paul Ince and Nicky Butt.

The question again posed by Sunday's capitulation is who, if any, of the current gang can be the midfield general, with Michael Carrick a classy yet passive presence, and Fellaini only three appearances into his career at the club.

He and Carrick appear first-choice for Moyes's engine room. While each was supine against City, serious questions will be asked of Ashley Young and Antonio Valencia, two dedicated wingers who continually neglected their tasks of closing down and tracking back. As City's attack posse of Touré, Fernandinho, Jesús Navas, Nasri, Sergio Agüero and Alvaro Negredo terrorised United, Young and Valencia went missing in action. Yet Nani, who is erratic, and the callow Wilfried Zaha, are no bankers as better replacements.

With Carrick and Fellaini too similar for a central pair – each are instinctive holding operators – Moyes gazes at his alternatives and sees the 39-year-old Giggs, Cleverley, who is still to prove he can be a midfield don, and the often disappointing Anderson. Another is Jones, but both player and manager are minded he is best in defence.

Kagawa is the most intriguing of Moyes's alternatives. Yet as a No10 by choice, who so far has not been fancied by the Scot, there appears little chance of him dislodging a Rooney now recast as the main man following the sparkling form that continued against City.

Might Kagawa prosper further back? Alongside Carrick in a two, or in a midfield trio if Moyes was to realign the shape to 4-3-3? These are some of the considerations that may cross the manager's mind as he decides how best to recover from a beginning that has yielded only seven points from his first five matches.

As Nemanja Vidic, the captain, said: "We have to bounce back. That is the way we have to think. We have lost and there are some things we can improve on but the most important thing is to win the next game." Rooney, whose late free-kick took him to a record 11 in the fixture, complains of the sloppiness that cost United.

"The way we conceded the goals, one just before half-time and two straight after, is not good enough," he said. "We know we have to improve on that, to stop giving these sloppy goals away and capitalise on some of our good play."

Those goals were shipped because of a United midfield that waved City on to David de Gea's goal.

In the resource deficit Moyes faces here, he sees why Ferguson would field Rooney further back. The ploy harvested match-winning performances, as with last season's 2-0 victory at Stoke City where, alongside Carrick, Rooney beat him 81 to 75 in completed passes, while again illustrating the requisite zest and vision.

Yet the 27-year-old's disquiet at being played out of position by Ferguson means he can be no solution for Moyes, and that encapsulates the manager's problem: as he seeks to stop United being overrun again, from where – and how fast – can he find one?