The Dutchman worked the ball onto his left foot at the Stadium of Light and fired in a shot but it took a deflection off Titus Bramble and will go down as an own goal against the Black Cats centre-back.
Following the FA Cup tie at Chelsea, van Persie has now gone nine games without scoring with his last strike coming in the home win against Everton in February. However, the manager rejects any suggestions that the 29-year-old needs a break at this stage of the campaign.
"Robin doesn't need a rest, that’s for sure," insisted Sir Alex. "He's a strong lad with a great physique.
"It's disappointing he wasn't awarded the goal at Sunderland – I can understand that because it took a wicked deflection. His shot was fantastic – it was hit with such venom that it’s not surprising it took a deflection. But his ability to manoeuvre his position at that point was excellent. The goals will come. All strikers have little dry spells – you always hope it ends quickly. It's just part of being a striker."
After bagging the late winner in the corresponding derby fixture at the Etihad Stadium, the stage is set for van Persie to net against City again on Monday. Sir Alex says he can draw on his own experience to offer advice to strikers when it comes to taking chances.
"I didn't have dry spells [as a striker]!" he laughed. "I remember I had a spell at the start of one season when I had a little knee injury and didn't score until October and I still ended up with 30-odd goals!