Milan won 3-2 at Cagliari to keep alive their title hopes.
"Huntelaar's goal was extraordinary," Seedorf told Sky Sport. "I am happy for him and was always aware of his ability to strike the ball.
"We played a good game in the first half against a tricky Cagliari side. Despite two errors at the back which we were made to pay dearly for, I think we showed good character during the game.
"This is just the first step. Now we must take six more to keep on the pressure at the top."