Ferguson claimed Van Persieâ€™s second, a volley beyond Brad Guzan after latching on to Wayne Rooneyâ€™s 40-yard pass, was the â€˜goal of the centuryâ€™.
The United chief said: "Never mind goal of the season, it could be goal of the century. He did something similar for Arsenal, heâ€™s a special talent for sure. He has been unbelievable all season.
"For the first six months he was incredible, but he had that little dry spell. I knew when he scored the penalty (at Stoke) that he was back. He has been truly unbelievable. Van Persie was such a great player for Arsenal that when he became available at the end of his contract and we went for him, we knew he would make a fantastic contribution.
"In terms of impact he has made as big an impact as Cantona â€” he was an impact player. I have been very lucky with strikers and Iâ€™ve probably had 10 great strikers.
"I think we had an expectation with him. He was sensational with Arsenal. When we concluded the deal Arsene said he was a better player than even I thought. He was right."