Argentina striker Aguero struck twice as City hammered their rivals 4-1 in their Barclays Premier League meeting at the Etihad Stadium.
The emphatic nature of the win over the champions clearly signalled City's title ambitions under Manuel Pellegrini but Aguero knows there is much more hard work ahead.
Aguero said: "We will keep our feet on the ground - the manager won't let us put our hands down anyway - and keep on battling.
"It's important to keep going. There are a lot of teams capable of winning the championship, but we are going to do everything we can to be the team that wins it.
"I'm very happy for the victory and the three points. We are near the top and we want to be at the top.
"I like scoring against United, it's enjoyable, but the most important thing is to win the matches and that's all I think about."
In terms of sending out a message, City's win has been compared to their 6-1 thrashing of United at Old Trafford two years ago.
They went on to win the title the following May but Aguero is not reading too much into that.
The 25-year-old, who was also on target in that famous win of October 2011, said: "It's difficult to compare with the 6-1, this one has different players, but the important thing is to win and it doesn't matter if it is by four, five or six goals.
"We won, we scored and are winning the matches, that's the important thing."
City make a quick return to action as Wigan, their conquerors in last season's FA Cup final, visit in the third round of the Capital One Cup tonight.
Much has changed since the Wembley clash in May with both clubs having changed managers and City spending more than B£90million on new players, while Wigan were relegated to the Championship.
City are likely to make changes with defender Micah Richards, who has missed the start of the season with hamstring trouble, among those likely to come in.
Richards did not play in the cup final but sees the latest tie as an opportunity to put its memory firmly in the past.
The 25-year-old told the club's website, www.mcfc.co.uk: "I wasn't involved against Wigan, but there was definitely something lacking.
"Wigan have always played us well and have been a bit of a bogey team, but I would never say the guys weren't up for it because we always want to win, but I just felt they wanted it more on the day.
"That game is in the past now but we have to make sure we put things right in this game and try and progress in the competition."