United missed out on the title on the last day of the season at Sunderland last May and Ferguson has been pleased with their response.
"The players have been galvanised. Their spirit, concentration and focus have been excellent," he said. "We have 25 wins from 30 games, which I think is a record, and that's all down to the efforts of the players.
"We just have to win games and that is the important thing to focus on."
On Van Persie, who had been without a goal in seven games, the Scot added: "When you do get back scoring you get back into the stream. I'm not sure if it was an own goal but it was a wicked hit from him, a fantastic shot.
"Sunderland had a real go at us. We had a few crosses to deal with and it was an important win."