The pair met in the Community Shield in August, and they'll meet again in the FA Cup semi final on Sunday.
In between, things haven't worked out as they'd hoped.
There's a rational approach to answering the question, but since when can you apply the word "rational" to owners of football clubs?
Will Roman Abramovich be happy with the FA Cup? Was he happy with the Champions League?
This is a man who has sacked coaches after winning doubles and the major European competition.
Those decisions may have cost him a lot of money, but did they improve Chelsea?
No. They caused instability which continues to this day and made the club unattractive to top managers because they know they won't get time to do a job.
Each departure left a power vacuum that was filled by players and left the new manager with an even harder job. Abramovich escapes major criticism from the media and Chelsea fans probably because they realise that without him, Chelsea wouldn't have been regular trophy winners over the past decade.
Instead of targeting him for sacking top-class coaches such as a Mourinho and Ancelotti when they don't deserve to be dismissed, they target Abramovich's puppets in the boardroom, or coaches such as a Benitez, who has done little wrong.
If Benitez wins the FA Cup he will have done a lot right with an ageing, divided and transitional team.
Sometimes it's better to be lucky rather than good in football.
Chelsea were out of the league title race quite early this season, out of the Champions League, likewise. So to be in with a chance of the FA Cup and the Europa League by mid-April is relative success, especially given the constant changes at Stamford Bridge.
Chelsea have a great recent record in the FA Cup: they've won it in four of the past six years.
Pre-Abramovich the club would have been delighted with that level of success, but now?
The FA Cup is the second-most-important trophy to win in England after the league.
But it's all about expectation. At the start of this season, Chelsea and Manchester City fans expected their sides to be challenging for the Premier League and the Champions League. They were the priority and the FA Cup was long way behind, a consolation.
It's a shame that it has come to that. I've spoken to former players who say that in the 1960s, the FA Cup was a bigger deal than the league and the European Cup.
Now, it's a distant third; the lower prize money dictates that. When clubs invest as much as Chelsea and City, there's a pressure to win more than the FA Cup.
Because of their relative failings this season, both will be taking Sunday's game very seriously.
City need to win the FA Cup.
They haven't put up a sound defence of their title and were embarrassed in Europe. Too much of their dirty linen has been washed in public, and too many players in their excellent squad haven't performed to their capabilities. City are good enough to go to Old Trafford and win. as they did on Monday, yeet not good enough to match United's consistency.
They didn't win a trophy for 35 years until their 2011 FA Cup win and the novelty of winning trophies still includes all trophies.
They want to win another FA Cup, but it will also be a consolation prize for a season which hasn't matched last year.
Still, City's biggest failure this season was in Europe. Not winning a single game is unforgivable for a club with their squad, but pressure didn't build on Roberto Mancini because he'd led City to the Premier League only months before.
I doubt Mancini will be at City next season. He has been unable to get the best out of his best players for two seasons.
But is changing the manager frequently the right thing to do? After seeing what happens at Chelsea, I'm not convinced that it is.
It seems bizarre that we're talking about City "only" winning an FA Cup when they went so long without coming close to a trophy.
But that is the way football works.
An FA Cup win for either will limit the pain of losing out on a league title they so coveted. But it will only ease it; it is not a cure. Only the owners know what remedies they will seek once the season is done.
Andrew Cole's column is written with the assistance of European football correspondent Andy Mitten.
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