The 26-year-old scored twice as United leapfrogged Manchester City at the top of the Premier League table.
"Alex [Ferguson] can tell you if his form is near the top or slightly off it but he always looks to be a player in form to me," Hodsgon said of Rooney.
The Baggies boss also said that England will miss Rooney during Euro 2012 due to his two-match ban.
"You'll find that after those two matches a lot of people will be saying Rooney would have helped England's chances if he'd played," he said.
The defeat to United leaves West Brom 14th in the Premier League with 35 points from 28 games.