The sides go into Wednesday's cup quarter-final clash at the Imtech Arena in polar opposite form in the league, with unbeaten Bayern 13 points clear at the top and Hamburg second-bottom after losing their last six games.
That sequence leaves Hamburg, who have never been relegated from the Bundesliga, just four points clear of basement club Eintracht Braunschweig.
However, despite their opponents' abject form, Guardiola maintains the threat of Bert van Marwijk's men must not be underestimated.
"It would be the biggest mistake if we look at the Bundesliga table," said the Spaniard.
"Their situation makes HSV very dangerous. Although they do not have much self-confidence, they have good quality.
"We have a great opportunity to take the next step towards (the final in) Berlin."
Franck Ribery will be absent for Guardiola on Wednesday, having undergone surgery to repair gluteal bruising, although Bastian Schweinsteiger could make a return from his long-term ankle problem.
On Schweinsteiger, Guardiola urged caution in recalling him to the side, stating: "Basti was injured for more than two months. He needs time."
Referring to Ribery, he added: "He's an important player for us. We have to support him and we wish him a speedy recovery."
