Sunday was nothing short of a derby day disaster for Manchester United, who were mauled by their noisy neighbours.
Manchester City strolled to an emphatic 4-1 success thanks to doubles from Kevin De Bruyne and Riyad Mahrez after Jadon Sancho had briefly given United hope.
Ralf Rangnick could only watch as United's dreadful defence was torn to shreds time and time again by City, who ran riot in the second half with De Bruyne pulling the strings.
But was anyone really surprised by the end result given how hopeless Manchester United have been defensively? And not just this season, either - but for a long, long time.
Blame has been persistently heaped on Harry Maguire in recent weeks, and rightly so, but United's entire defence were carved open almost at will by Manchester City on Sunday afternoon.
United spent around £175million on the defensive unit that was embarrassed by their bitter rivals on Sunday.
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And while that may seem ridiculous, it's worth pointing out that Manchester City themselves spent a lot of time, and money, before stumbling upon the magic formula at the back.
Joao Cancelo, Aymeric Laporte, John Stones and Kyle Walker were the contingent tasked with defending Ederson. That quartet set City back a whopping £214m - and that's without throwing Ruben Dias into the mix, who cost a further £61m.
Taking those figures into account, it's easy to see how building a title-winning defence can add up.
Cancelo has, to a degree, pushed the very boundaries of what's expected from a full-back in the Premier League. But City paid handsomely to prise the classy operate away from Juventus, with a fee of £58.5m needed to convince the Italian giants to do business.
City shelled out an identical fee for Laporte, who has struck up a rock-solid partnership alongside both Dias and Stones, who cost City £50m back in 2016.
When you factor in the £47m sum that City paid to Tottenham to bring Walker to the Etihad, City's spend dwarfs that of United's - although they have certainly got more bang for their buck.
But once United have licked their wounds from Sunday's mauling, they should take encouragement from City's previous outlays.
There's still scope for Manchester United to build a formidable defensive unit - but it will require big decisions and even bigger investment in the months and years ahead.
The likes of Maguire and Aaron Wan-Bissaka have struggled for too long now and questions have to be asked of their long-term future. Manchester United will struggle to challenge for titles until they shape up defensively, just like City have.
It is worth remembering that City have signed their fair share of duds down the years too.
The £42m signing of Eliaquim Mangala immediately springs to mind. And as calamitous as the Frenchman was, City have manage to rebound and dominate the Premier League after recognising and amending their expensive mistake.
The onus is very much now on Manchester United to do the same if they are ever going to close the gulf that has emerged between themselves and their rivals.
There was a time, many years ago, that people would have scoffed at the prospect of Manchester United following Manchester City's lead. That's not the case anymore.
All fees courtesy of Transfermarkt.
