Instead, Ferguson had to make do with an incredible 5-5 draw as the final act of a career unsurpassed in the British game.
"I was waiting for some Fergie time at the end," Van Persie joked.
"It didn't happen but to score 10 goals was good fun for everyone, so I think the fans are pleased."
Ferguson opted not to speak with the media afterwards. His thoughts would have been fascinating, though, for at any other point in his career the hairdryer would surely have been turned up full volume given how the match unfolded.
Shinji Kagawa and a Jonas Olsson own goal had United cruising after just 10 minutes and when Alexander Buttner drove home a third midway through the first half, it seemed Ferguson would enjoy a victory cruise on his final day.
Even after James Morrison and Romelu Lukaku cut the gap either side of the interval, United quickly restored their three-goal cushion through Golden Boot winner Van Persie and Javier Hernandez.
Yet it proved to be the prelude for the most astonishing of comebacks as Lukaku and Youssuf Mulumbu netted amid chaotic scenes before Lukaku completed his hat-trick.
Both sides formed a guard of honour for Ferguson before the game, with the West Brom supporters joining their United counterparts to applaud the Scot after the final whistle.
"After 26 and a half years at United and, before that, at Aberdeen, Sir Alex deserved it," Van Persie said. "He's unbelievable and what the West Brom fans did was a nice touch. It's right to show respect. It doesn't always happen in football but today it did and I'm glad."