Rooney insists Forest manager Sean Dyche's tactics worked perfectly, while also taking aim at Liverpool's "lack of fight" on the day.
The Reds now sit eleventh on the Premier League table after a sixth defeat of the season.
Rooney told Match of the Day: "Yeah, they did, and I think that's a concern when your captain is speaking like that about the players lacking fight and not winning second balls and winning the challenges.
"But if we look here at how Nottingham Forest prepared themselves against Liverpool… they allowed Liverpool to come onto them early on and they were sucking Liverpool into traps all afternoon."
Reds skipper Virgil van Dijk said afterwards: "We were not good in terms of battles, challenges, the fight, too rushed. It's a very difficult situation at the moment.
"It's a problem. Everyone in the team has to take responsibility as well. Football is a team and everyone has to take responsibility."