City are unbeaten in 18 matches in all competitions this season, holding an eight-point lead atop the Premier League and having already qualified for the last 16 in the Champions League.
Ahead of hosting Feyenoord on Tuesday, Guardiola said it was nice for his side to be placed among Europe's elite — but he said they had plenty of work still to do.
"For Manchester City, a team that still needs a history in Europe, that is a big win," the Spaniard said.
"That doesn't mean we are favourites to win the Champions League, but it's nice.
"People putting us there is a big honour but that does not mean we have done anything because we haven't. Manchester City still have a big history to build in Europe."
With City having won all four Group F matches ahead of facing a point-less Feyenoord, Guardiola plans to rotate his squad for Tuesday's clash.
The former Barcelona and Bayern Munich coach believes a testing period awaits his side, who have 12 matches to play before the end of the year.
"We don't have a big squad. It is a big pity we lost a month-and-a-half of Vincent Kompany and now John Stones," Guardiola said.
"To win the titles we need all the squad, especially important players like John and Vinny.
"On the other side, we have an opportunity. We have to play 12 games in a short space of time with only three central defenders and one of them is a risk in Vincent, [who is] only just back."