On a day when Arsenal, not for the first time this season, barely troubled the opposition goal, a brace each for Van Persie and Hernandez blew Wigan away.
It was bad enough for Arsenal fans to see RVP move to Old Trafford. It is sad to witness their bitterness at his clearly understandable decision. And the discrepancy between the forward options at the two clubs is a tragedy to behold.
United allowed Dimitar Berbatov to leave in the summer, but they still boast Rooney and Welbeck, as well as the aforementioned pair, among their ranks.
Van Persie and Rooney are, of course, two of the best strikers in the world.
But any of United's four frontmen would be well worth a place in the Arsenal starting line-up.
It is little short of staggering that United are thought to be considering a move for Lewandowski, when their midfield is so clearly in need of a top class addition.
Surprising, too, that Arsene Wenger can sniff at the notion of getting Demba Ba for a knockdown price, due to his conviction that Olivier Giroud will soon develop into a similar force.
Ferguson did not back off from his pursuit of Van Persie on the basis that Rooney is a roughly similar player. And now United are reaping the handsome reward of that successful pursuit. It looks like it will win them the title. I myself had hoped that Van Persie and Rooney would step on each other's toes; that hasn't transpired and it serves as a timely reminder that if great players have the right attitude, you can't have too many of them.
We saw again today that United have variety as well as quantity up front. Van Persie can score in almost any way; Hernandez again showed his rather more specific value. He has an almost magical ability to be in the right place to gobble up ricochets and mishit shots. He's a pinball wizard.
United have Van Persie, Rooney, Hernandez, Welbeck.
City have Aguero, Tevez, Dzeko, Balotelli.
Arsenal have Giroud and some out of position wingers.
And the gulf in goalscoring options is reflected in the the Premier League table.