After Rickie Lambert and Morgan Schneiderlin had scored either side of Van Persie's first goal, the Dutch international looked set to get his first taste of the famous hairdryer treatment after wasting an opportunity to draw level with a cheeky penalty attempt that was saved by Kelvin Davis.
However, Van Persie's late double salvo, which took his Premier League tally to 100, turned the game on its head and earned United a 3-2 victory, much to Ferguson's - and the former Arsenal striker's - relief. The United boss said of Van Persie: "I was surprised because every time I have seen him take a penalty he rattles it in the corners."
Ferguson, celebrating his 1,000th league game in charge of United, added: "He made up for it, though. He had six attempts on goal and was a real threat.
"His first goal was absolutely magnificent - the control and then to bury it away. It was a really, really good goal. His header was excellent too, but he has been a terrific player for us.
"I just thought we started the game so well and went a goal down when we were controlling the game. That puts you on the back foot a bit. We got an equaliser at the right time and that gave us time to organise ourselves and make sure we controlled the second half. It didn't go that way and I thought Southampton for the first 20 minutes were very good."
While Ferguson struck a relieved figure, counterpart Nigel Adkins was left to rue what might have been. Just like at Manchester City two weeks ago, his side gave up a 2-1 advantage to lose 3-2 and, while frustrated, the Saints boss was keen to highlight the positives.
"For a newly-promoted club we have scored two goals in open play against a Man Utd side packed full of experience," Adkins said.
"Lambert had an exceptional game, Jason Puncheon had a superb game as did Adam Lallana. I thought they had worked very hard and we made the substitutions to bring more energy into the side.
"You get punished at the highest level. [Nathaniel] Clyne slips and Van Persie puts the ball into the net. In the second half, we were buzzing. But they kept possession of the ball. It's two corners we have conceded from."
Source: PA
Source: PA