Van Persie struck in the final minute to seal a 2-0 win over West Bromwich Albion before lifting his shirt to reveal the message: "RIP Tchuna we will never forget you".
It was confirmed the message related to a close friend of the Dutchman, who died on Friday night.
Not that it stopped the eulogies to a man Sir Alex Ferguson has already said represents the final piece of his jigsaw and who was required today to settle a few nerves after initially starting on the substitutes' bench.
"He is a fantastic player," said Ferguson. "He came on and changed the game for us.
"Every time the ball came up to him he got hold of it and turned on them. They were having to go back to their box all the time and he has done well."
Van Persie's superb curling effort kept United seven points clear of Manchester City and earned maximum points from a fixture that did not turn into the cruise they expected after Gareth McAuley's early own goal, which Ashley Young said he was going to try to claim despite his part clearly being a cross.
"Where there's a will," said Young, who scored in a similar manner when the two sides met at The Hawthorns last season.
West Brom have improved since then, as Ferguson acknowledged.
"They were a very resilient, stubborn team," said the United manager. "They worked really hard on their defending and closed all their ranks. You have to deal with that but the slowness of the pitch killed our speed a bit."
The former United goalkeeper Ben Foster kept his old club at bay in the first half, making a superb save to deny Young.
Not that the West Brom manager Steve Clarke was surprised at such heroics. "Ben Foster made some good saves," he said. "That's why we spent our whole transfer budget on Ben in the summer."
After a difficult first half the visitors came to life after the break, forcing United into a tactical changeand Van Persie's introduction.
"It is not demoralising," said Clarke of Van Persie being brought into the action. "The fact they had to bring some of their big guns off the bench shows how well we were doing. In the first we were too timid. We spoke at half time about being too respectful and in the end, the score line doesn't reflect the way we played."
Clarke rejected suggestions the pitch, which needed to survive an inspection for the game to go ahead, was too difficult.
"We used to play on pitches like that all the time," he said.
"It is part and parcel of the game. You don't look for games to be called off for no reason and there was no reason today."
United now move on to a trip to Wigan Athletic on Tuesday, with Ferguson hopeful of reinforcing his squad with a few fresh faces.
"It will be a hard game," said Ferguson. "But hopefully we can freshen up again. Possibly Phil Jones will be ready and Rafael will be ready.
"We rested Javier Hernandez today, and also Ryan Giggs and Paul Scholes, so we have enough freshness to bring in."
* Press Association