Three European centre-backs Manchester Uni could target this summer amid Harry Maguire speculation

Manchester United have spent significantly to strengthen their defence in recent years, but their work is far from complete.

The Red Devils’ expensively assembled backline was ripped apart once again on Sunday afternoon, as local rivals Manchester City stormed to a 4-1 victory at the Etihad Stadium.

Whichever permanent manager comes in to follow Ralf Rangnick this summer will likely make strengthening the leaky defence a key priority, with reports last week saying the Red Devils want to bring in a centre-back in the off season.

But where do United turn next to improve their back four? Once again, the Red Devils will probably have to spend significantly to get a top-level player at the back, and here we pick three strong contenders.

Matthijs de Ligt - Juventus

We’ll start with the most possible of the three - Juventus’ de Ligt, who could be on the move this summer.

The 22-year-old has been linked with a transfer as his contract set to expire in 2024, and Juventus don’t want to let his deal run down.

De Ligt hasn’t quite lived up to expectation that greeted his arrival in Turin due to both injury and form, but he remains a top talent and one certainly worth buying.

One issue that could complicate this move is the competition for his signature, which is likely to be intense, with the likes of Barcelona and Chelsea reportedly among his keen admirers.

Jules Koundé - Sevilla

The Sevilla centre-back has attracted plenty of attention over recent transfer windows, with Chelsea heavily linked in the past.

Last summer, his exit was blocked as Sevilla had bold ambitions to challenge for Spanish title bid, and they are still just about in the mix heading into the back-end of the campaign.

Koundé has a release clause of around £68million and competition will again be fierce this summer.

But at 23 years of age, the Frenchman is among the best young centre-backs in the world, and would be a stellar investment for United.

Pau Torres - Villarreal

This will certainly be a familiar name to Manchester United fans. The Villarreal star has been heavily linked with a move to Old Trafford in the past, while Tottenham Hotspur had an offer for him accepted in the summer - as you may have guessed, they failed to complete the deal.

In the end, Torres decided to stay and represent his hometown club in the Champions League. The 25-year-old has maintained brilliant form this season despite Villarreal’s early struggles.

He and his club are now challenging for the top four and impressed with a 1-1 draw against Juventus in the Champions League last 16 last month.

The Spain international is a left-footed centre-back and one of the most talented in his class in Europe.