The strangest of strange seasons for Manchester United fans continues. After the recent humiliation at the hands of Liverpool's Steven Gerrard and his merry-men, the Red Devils are now on a "run" of victories.
The comeback against Olympiakos was straight out of the United locker, as if Sir Alex Ferguson had written the script himself after several packs of chewing gum and the finest bottle of Chateauneuf-du-Pape from his cellar.
The performance and subsequent hat-trick from Robin van Persie was the most electric 90 minutes of football at Old Trafford this season, until a Greek defender decided to go through the back of RvP's knee.
But when one door closes another one opens, and on Saturday against West Ham we saw David Moyes take a calculated gamble in the Dutchman's enforced absence.
And it was a thing of beauty.
The 4-2-3-1 that Moyes should have been playing all season worked better than ever.
The players knew what they had to do, and most importantly: did it.
Rooney played as the lone striker, but he was not alone. His movement allowed Mata and Kagawa to get close to him, with Ashley Young offering width from the right.
It's worth noting that when Rooney scored his wonder goal from just inside the half-way line, it was Mata running close to his inside, demanding the football be played to him.
It is this kind of support that United have lacked all season and the reason why the club have only a paltry 34 goals to their name in the Premier League this year, per Squawka.
Kagawa also made the best appearance of his United career, protecting the left side, but without inhibiting his own attacking game.
The formation allowed him to drift into the areas that 4-4-2 will simply not allow. When we have seen Kagawa in the "wingers" role in Moyes' favoured formation he is half the player, restricted by the rigidness that 4-4-2 demands, unable to create on the inside or join the striker.
Against West Ham, Kagawa was allowed to join with Rooney and Mata, and their average positions were almost the same as one another, as displayed above, per WhoScored.com
With a busy Marouane Fellaini and Darren Fletcher patrolling the midfield, all three individuals were able to invent and link together.
It was fantastic to see and hopefully a sign of things to come. Wing-attack is a pointless exercise when your wingers are not masters at crossing the ball. You should always play to your strengths, even if this busks your ideology. Maybe Moyes is starting to understand this?
So this now begs the question: What happens to Robin van Persie?
The answer is nothing. Not in the short-term future.
With United still very much in transition it would be impossible to play Rooney in the striker position every week. His added value and work rate means he will be needed at times in a deeper role.
If the van Persie who turned up against Olympiakos starts to make regular appearances when he returns from injury there is no reason he could not fit into the exact same 4-2-3-1 that we witnessed on Saturday.
He has the ability to drop deeper and link, and interchange with Kagawa and Mata, just as Rooney did at the weekend.
It would then become a question of form and healthy competition through rotation. The best players get in the team, not the highest paid.
If RvP was out of form then there would be alternatives. Danny Welbeck falls into the equation nicely and fits this tactic and formation well. But the way that Mata and Kagawa play as a dynamic support function to the striker is the direction that United should be heading in.
That point is more important than if van Persie starts in the team.
Which system should David Moyes use for Manchester United?
It is debatable whether Kagawa will still be a Red Devil after the next World Cup, but he finally might have found a place in the United starting line-up.
Both he and Mata now need a run in the side together, and Moyes has to believe now that his pragmatism this season has not helped his football team.
The future of Manchester United should be a fluid continental system and not the old styles we saw in the 1990s.
4-4-2 is dead, but the traditions of United playing attacking football are still very much alive.