So we sold De Bruyne and Lukaku. Get over it.

Reuters

At the end of last night's Champions League quarter-final tie between Manchester City and Paris Saint-Germain there were two sets of opposing schools of opinion at work on Twitter. And both involved, exclusively, Chelsea supporters.

The first concerned praise for City beating PSG and progressing to a semi-final, the only English club that will do so this season. For every Chelsea fan sportingly slapping City on the back, there was another, soaked in bile, branding any such individual as a traitor to the cause. This branch of football's tribalism has also manifested itself in the conflict of conscience Chelsea followers have at seeing Tottenham doing so well this season. Chelsea's dismal, trophyless term has rendered many in a state of catatonia, numbed by the failure to achieve any of the club's objectives, including retaining the Premier League title, but also accepting the mediocrity that will leave the club in or around mid-table on May 15.

The second movement concerned Kevin De Bruyne, Belgium's best known Prince Harry tribute act, who scored the scorching goal last night that made the ultimate difference between City and PSG. Chelsea, as you might recall, bought the-then 20-year-old from Genk for £7 million on the final day of the 2011-12 winter transfer window. But, being Chelsea, he remained at Genk for the rest of that season, before being loaned out to Werder Bremen the following August. A successful, goals-a-plenty season later, he returned to Chelsea, by then under the management of José Mourinho. Mourinho gave assurances that De Bruyne would play for him and, being a capable attacking midfielder, especially down the flanks, he certainly seemed to fit the Mourinho preference, previously seen with Arjen Robben, Damien Duff and Joe Cole during his first spell in charge, to title-winning effect.

However, the ginger winger somehow failed to convince the club that he was worth keeping. Mourinho himself explained that De Bruyne had "failed to compete" for a place, suggesting either an attitude issue or a reaction to Mourinho's training approach. And so, De Bruyne was offloaded in the January to Wolfsburg, where he spent the rest of the 2013-14 season, and the 2014-15 season, building up the solid reputation (including being voted by journalists the German league player of the season) that made City fork out a club record £55 million.

Which brings us to last night. Frankly, what little we saw of De Bruyne from the stand at Stamford Bridge didn't exactly convince us that he was the Chosen One. Like all the other attacking midfielders Chelsea have bought and sold - and that list runs the length of the Bayeux Tapestry - he showed plenty of running and endeavour, but certainly didn't display the sort of talent that justified City spending so heavily to acquire. So maybe Mourinho was right.

Former Chelsea striker Tony Cascarino doesn't think so. In his column in The Times today, he wrote: "I can't understand how [Chelsea] and José Mourinho decided to let him go. He may not have played that many games for them but surely he showed his potential in training every day?" adding "I don't know how Chelsea couldn't see his potential." Mourinho, like his mentor Sir Alex Ferguson, has never held back in showing short shrift to players that don't meet his requirements. Just look at Juan Mata, who went from Chelsea's player of the season to lucrative sale to Manchester United. Clearly, though, De Bruyne's results in Germany spoke for themselves, and even with their reputation for unwarranted largesse (a trait obviously shared with Chelsea), City saw in the Belgian something they needed. Last night, that investment may have singularly paid off.

But for Chelsea fans, however, to bemoan offloading De Bruyne to begin with is wasted energy. Likewise, Romelu Lukaku, whose own brief appearances for Chelsea were not particularly convincing, even if he disappeared on loan to West Brom and Everton for three seasons, where he scored like a demon.

It is galling to see, and can be likened to owning the winning lottery ticket that slips through your fingers on a windy day (or, as Danny Baker put it on Twitter, "Like seeing the girl you dumped at 17 go on to be Jennifer Aniston."). But what can you about it? Nothing. Absolutely nothing.

Chelsea's transfer policy leaves an enormous amount to be desired. As this blog has frequently commented on (actually, make that 'constantly'...), the club's husbandry of young talent, loaning them out, having them win tropies in the youth squads, but never letting them see the light of day in the first team, is an absolute disgrace, no matter what the footballing or even business rationale the club may put behind it. And, if Chelsea let De Bruyne and Lukaku go because their player development processes aren't sharp enough to recognise talent, or because they didn't fit the ethic of the manager, then the blame for that needs to fall squarely on the shoulders of Michael Emenalo, the club's technical director, or on Mourinho.

But then it is also possible that, like us in the stands, Mourinho just didn't see anything in either player to convince him. It was perplexing that Lukaku would go off on loan, score a decent number of goals, and then return to the Bridge to bumble about unconvincingly. The question is, was he a diamond in need of polishing? Was Mourinho the right manager to apply the polish? Or did the player simply not fit the manager?

The point of all this is that, there's not a lot of point in moaning about it. Chelsea moved on. They sold David Luiz and bought Diego Costa and Cesc Fàbregas with the proceeds, winning the Premier League on the back of their endeavour. Lukaku might, we read, still come back to Chelsea, as if to prove a point (and in the process, earn Everton a princely sum). De Bruyne may well turn out to be an expensive impulse buy for Manchester City. Chelsea may need to do something about improving their player development processes. Either that, or buy a better crystal ball. But to moan about decisions to sell average-looking players who go on to be above average, well that's just tough. Time to move on. As they did. Or at least as far as this coming Saturday, when City - including De Bruyne - come to Stamford Bridge.