Kevin De Bruyne and Riyad Mahrez struck derby doubles as City condemned their rivals to a chastening Manchester derby loss.

De Bruyne's early opener was superbly cancelled out by former City prospect Jadon Sancho, only for the Belgian to strike his second and Mahrez to grab a second-half double in a deserved win against Ralf Rangnick's side.

It was a rare Etihad Stadium defeat for United, whose hopes of a fourth straight away win on enemy turf in all competitions were hit inside five minutes when the hosts all too easily sliced them open and ended with the Premier League champions in cruise control as Pep Guardiola's leaders restored their six-point advantage over Liverpool at the top.

• Man City 4-1 Man Utd - Match report and highlights
• Neville: Embarrassing Man Utd threw towel in at Man City
• How the teams lined up | Match stats
• Watch PL highlights for free on Sky Sports

Neville: Players have to get spirit back

Speaking on the Gary Neville Podcast, he said: "We watch every team in the Premier League each week and we come away thinking they work hard and they try to be compact. We see they're organised and that they have a game plan.

"I've watched Manchester United from the beginning right the way to now, and even in the last two or three months where Rangnick has had a pretty good run of losing just once in a run of 15, but there have been games where the warning signs have been there and David de Gea has kept them in games.

"We knew this period was coming where they would play Atletico Madrid twice, Liverpool, Tottenham and Man City all in the space of a month. This was the first proper team they faced and they've been obliterated. It was no different to when Ole Gunnar Solskjaer was in charge and it's no reflection upon Rangnick.

"I don't put any blame on him for what's happened today. You asked the question before the game if he would be here next season... he won't be the manager, absolutely not. The question is, which players will be here at the end of the season?

"I've been critical of them in terms of their spirit, the leaks, the lack of togetherness and it comes hurtling towards you in a game like this. You find out if you've got a spirit or not as it's OK coming back in games against Brighton, Southampton or Villa.

"They've got a £350m budget and have spent £1.2bn on this squad so you expect them to stay in games. But when you play against the top teams, you'll get pulled apart. What we saw at the end of this match was a spiritless Manchester United.

"That's the biggest concern as those players have to get that spirit back. They've got to get the fight back. There were rumours before the game about Cristiano Ronaldo. What's happened to him today? Rangnick said it was a hip injury but it was coming through on social media that there was nothing wrong with him.

"There's been rumours that Edinson Cavani doesn't want to play even though he's fit. Again, not great. All these things are emerging from the dressing room and we're not sure what's true. Varane and Shaw weren't here either today.

"There are these last-minute non-appearances. They add weight to the argument that something's not right in that dressing room. The biggest evidence you could see that something's not right was their response to going 3-1 down. In a derby.

"I had an appalling day at Maine Road years ago against Shaun Goater, but I knew full well that me and the rest of the players on the pitch would give our all. The effort and the spirit was still there. Today, United have made mistakes, they've conceded some great goals but they did throw the towel in during the last 25 minutes.

"92 per cent possession? Not just over five minutes, over 15 minutes. You wouldn't want that on your CV but those United players now have it which is really bad."

Former United captain Roy Keane branded their display as "shameful".

This is just the second time City have done the double over United since Guardiola took over and represented a second league loss under Rangnick, who was without Ronaldo, Cavani, Raphael Varane and Luke Shaw on Sunday.

Neville continued: "The Manchester United team surprised me as I thought they were going to play Rashford, Elanga and Sancho when we heard that Cristiano Ronaldo wasn't playing. United came out with a system that surprised us all with Fernandes and Pogba up front.

"For 25 minutes, I thought they played pretty well. There was real good intent and the back four pushed high up the pitch and they were close together. They were brave on the ball and they were going punch-for-punch with City.

"How long that would last, we didn't know, but we knew they didn't have a counter-attack in them with the two midfielders playing up front. They had to be more front foot, but it could have easily been 2-2 at half-time despite the two sloppy goals they gave away.

"Sancho had a really good chance just before half-time. I felt they were in this game then, particularly given their record over the last two or three years. It took City 25 minutes of the first half to get going although they always posed a problem down the left.

"Possession was pretty even midway through the first half which gave me the impression this game was different than I thought it would be. The problem for United was down their right with Lindelof, Wan-Bissaka and Elanga. More Wan-Bissaka, really.

"United's system caught them by surprise but City won the ball back quicker on the transition in the second half. You just felt like City grew into the game and it became too much. They were just so much better from the first minute of the second half and the ending of the game was just shameful for United.

"I don't use that word lightly. Manchester United's players didn't bother their backsides for the last 25 minutes. It was really terrible. I have great sympathy for the United players at this moment in time having to play against this great a Man City team.

"We had a situation like this towards the end of my time against Barcelona when they had Messi, Xavi and Iniesta. They just kept the ball off you and it was painful to watch. There's a little bit of an air of that about this City side but you've still got to have a go. You've still got to put it in, do the hard yards and run until the end.

"There's about 4,000 United fans in the far corner and by the end I think there was only about 1,000 left. I was watching them walk out minute by minute. I went from feeling that United hadn't responded well to the third goal to thinking this is not good at all. In fact, I was disgusted. I don't know what happened to them. I couldn't be more harsh.

"I've accepted that Jurgen Klopp and Pep Guardiola and their sides are exceptional, and you can start to think, 'when are we going to win the league again?' But even under Louis van Gaal, I never saw them give up. They gave up in the last 25 minutes."

What's next?

Man City host Sporting Lisbon in the second leg of their Champions League last-16 tie on Wednesday at 8pm, while Man Utd host Tottenham on Saturday Night Football at 5.30pm - live on Sky Sports Premier League.