Chelsea's late surge to glory, which saw them crowned European champions on Saturday, means that two of the richest clubs in England achieved breakthrough triumphs within a week of each other, suggesting soccer's balance of power could well be shifting.
The weekend after Manchester City, enriched by Arab oil money since 2009, took the Premier League title, Chelsea, bankrolled by Russian billionaire Roman Abramovich since 2003, won the Champions League for the first time in Munich on Saturday.
Their 4-3 penalty shootout win over Bayern Munich, in the Germans' own backyard, means Abramovich has now won the trophy he has dreamed of since buying into the club and transforming their fortunes nine years ago.
They also won the FA Cup this month but, perhaps just as importantly, their late-season form and triumphs after a poor start to the campaign point to a strong title challenge next season.
Manchester City's league title followed on from their 2011 FA Cup success, which was their first major trophy for 35 years.
Both clubs have been re-born, with City's recent rise, after Sheikh Mansour bin Zayed Al Nahyan took control three years ago, proving even more dramatic than Chelsea's.
The reason these successes could prove significant is that both clubs have broken new ground.
The wealth at the disposal of the respective owners, notwithstanding the fact they have to adhere to UEFA's new Financial Fair Play rules, means that they can build on these successes, attract the best managers and players and go on to dominate the English, if not the European game, for the forseeable future.
Manchester United manager Alex Ferguson always says that the hardest thing to do in soccer is to win a major trophy for the first time.
However, now that City have won their first title in 44 years, and Chelsea the Champions League, the ground rules appear to have changed.
Where does that leave United, and Arsenal, who dominated the game for a decade and are now increasingly having to play catch-up?
Where does that leave other big, historically successful clubs such as Liverpool, Tottenham Hotspur, Everton and Newcastle United? Trailing in their wake.
Ferguson, whose United side were pipped to the Premier League title by City on goal difference, summed up most people's feelings last Sunday.
"We know City are going to spend fortunes, pay stupid money and silly salaries," he said. "We know that happens. We can't do anything about that.
"We are not like other clubs who can spend fortunes on proven goods. We invest in players who will be with the club for a long time, who will create the character of the club and the excitement for our fans.
"We are good at that and we are going to continue that way."
United's chief executive David Gill, speaking at the club's awards evening last week, said United had the finances to compete in the transfer market this year, as the club look to bounce back from narrowly missing out on a record 20th title.
"Funds are available without a doubt," said Gill. "We can still pay very well in terms of wages and transfer fees. Clearly City have raised the bar. We have seen that with what they are prepared to pay for players and to them.
"But we need to move on. Financial Fair Play is just around the corner. It is a flagship programme for Michel Platini (the UEFA president) and how that is implemented and the sanctions that are imposed are going to be interesting."
City chairman Khaldoon al-Mubarak has hinted that the club may not spend as much over the coming months as they have in recent close seasons.
"We have a championship-winning team," he said in an interview on City's official website (www.mcfc.co.uk).
"We are not starting from the same point as in other pre-seasons. We have had to improve in a very dramatic manner. Now we have a nucleus. To improve further we have to harness that nucleus."
However, Chelsea could well spend big, while Arsenal are hoping Robin van Persie will remain to form a potent link up front with their new arrival Lukas Podolski. The Gunners, traditionally cautious with their spending, may now need to be a little more cavalier.
Talk of breaking up Chelsea's slowly ageing side will be tempered by Saturday's success.
Match-winner Didier Drogba, 34, is expected to leave in the close season, but skipper John Terry, defender Ashley Cole and midfielder Frank Lampard, the solid backbone of the team, show little signs of creaking to a halt just yet.
If Chelsea appoint the right permanent manager, and most think interim Roberto Di Matteo fits the bill perfectly, and buy wisely, then both City and Chelsea could dominate in the same way United and Arsenal did not so long ago.