City defeated West Brom 3-2 at the Hawthorns on Saturday to record their 13th straight wins in all competitions and extend their unbeaten record to 21 games.
However, Guardiola says that Serie A leaders Napoli, who themselves are unbeaten in the league to far this season will not simply roll over and let City get their own way.
"We need one more win to qualify but we are going to the team that are leading Serie A and everybody knows the type of football they play in their own stadium so it's going to be very difficult, but it's a great opportunity for us to book our place and we're going to try our best to do it," the Spaniard explained.
Whilst he was in a positive mood, Guardiola was quick to rubbish suggestions made by Liverpool boss Jurgen Klopp, who had claimed that City could win the Premier League title as early as January.
When asked if it was an unrealistic suggestion he rather bluntly replied: "Definitely. You are English - from a long time ago, did you see a champion in January? Me neither."
West Brom boss Tony Pulis was also reluctant to paint City as heavily title favourites after the game, saying that although well placed, plenty will change in the coming weeks and months.
"They are certainly one of the main contenders but it's a long season. They are in all the cup competitions. They've got to be fortunate with injuries and the bounce of the ball," said the Welshman.
"We've given them a game. There will be a lot of teams they go away to who will do the same.
"Winter comes - you see what happened to Manchester United when they went to Huddersfield and it was windy and it was wet.
"There are lots of obstacles they have to overcome. It is not in the bag yet."