It must be galling for Jose Mourinho. He may well be the manager of the most glamorous and wealthy club in the Premier League, but he doesn't have the players.
Even more annoying, Antonio Conte does and is doing what Mourinho could not do with the same lads last season.
Not just that, most of them couldn't wait to see the back of him and stopped playing for him before Roman Abramovic showed him the door for a second time.
Mourinho, on a human level, will obviously feel some pangs about Chelsea and what he achieved there.
His failure was caused by his temper and his reaction to the removal of the conditions he insisted on when signed up for a second stint at The Bridge.
Had he been allowed to build on the title win in 2014/15 without interference, it is difficult to imagine Leicester would have cantered to the title so easily last season and easier to imagine Mourinho trying for three-in-a-row.
But all of that is fantasy and Mourinho is long enough at it to remain rooted in hard reality. He knows that Conte has taken his group, added some improvements and made it his own.
He also knows that his own ragtag group of Fergie survivors, Ed Woodward's experiments in the transfer market and his own big ticket purchases doesn't match up to Chelsea.
That's why I can't find a way for him to win this FA Cup collision. Normally, I would have a big bet on Mourinho coming up with some trick, some tactic which would win him an unlikely victory but this time, I just can't see it.
When you take Zlatan Ibrahimovic out of the equation, you're left with a featureless group, dominated by Paul Pogba but only because of the column inches he fills, not because of anything he does with a football.
It is telling that Mourinho is about to reach for Marouane Fellaini as his physical answer to what is certain to be a ferociously focused and committed Chelsea team.
I watched Chelsea dismantle West Ham last week and when they had the game won, the signals went out from Conte.
He pulled his full-backs back, his wide players in tight and locked the game up. It was clever work and done with the kind of organisation that only comes when a really good coach is at his work on the training ground.
I believe he is the most complete manager working in the Premier League at the moment.
He believes that he can only free his creative men to work when the team is secure at the back and he has had that balance now for a long time.
Mourinho is also a believer when it comes to defence first and if it was any team but Chelsea in this FA Cup tie, he wouldn't hesitate to park the bus and play on the counter.
I don't think he has the players to do that and even if he did, Conte has Chelsea in an unbreakable rhythm