Rooney Carrick Welbeck Manchester United
Manchester United's Rooney, Welbeck and Carrick wait for kickoff following Man City's Sergio Aguero's goal in their English Premier League game, September 22Reuters

Wayne Rooney was quite disappointed with Manchester United's performance in the Manchester Derby after Manchester City thoroughly outclassed the English Premier League champions on Derby Day Sunday.

Rooney, who scored a consolation goal, was perhaps the lone bright spot in an otherwise forgettable outing for United, with goals from Sergio Aguero, Yaya Toure and Samir Nasri consigning the Red Devils to an embarrassing 4-1 defeat.

"The way we conceded the goals, one just before halftime and two straight after, is not good enough," Rooney told MUTV. "We know we have to improve on that, to stop giving these sloppy goals away and capitalise on some of our good play, which I thought there was bits of... it just came too late in the game."

Toure's goal on the stroke of halftime was a big blow, with Aguero, who had opened the scoring earlier, and Nasri netting within five minutes of the restart to end the contest.

"It (City's second) was a blow but we still thought we could get back in the game," Rooney added. "We've been two down many times before and we came out at halftime ready to get the first goal and that would have been game on. The way in which we conceded two goals so quickly killed the game.

"We knew at 4-0 that we obviously weren't getting back into the game but we had to keep fighting and pressing, trying to make a game of it to show the fans, and ourselves, the pride we have as footballers as it's never nice to lose.

"I thought during the last twenty minutes we played some good stuff. Had we done that earlier there might have been a different outcome, but it was too little too late."

United skipper Nemanja Vidic was also disappointed with the performance, terming it horrible. "To lose a derby game is horrible," Vidic told Sky Sports. "It's more difficult when you lose the game after this kind of performance.

"We were 4-0 down and it was really tough. We were never close to winning the game or even getting a draw. It's disappointing but we have to come back. We're down now but from tomorrow we'll try to be positive and win the next game and move on.

"From the first minute they tried to be aggressive," added Vidic. "I'd say they had more possession in the first 20 minutes and we lost a goal. We didn't get in the game from the first minute. Obviously this is what you have to learn and now, the next game, we try to win. That's the most important thing and we can't afford to look back."