After I saw the good performance from Real Madrid against Manchester City in the previous game they had in the Champions League, I think Real Madrid had an epic performance and Ancelotti knows how to beat even stronger teams because beating Gadudiola was not easy at all.
I think if Real Madrid has the good performance we saw from them against Manchester Cityagaginst other teams like Bayern Munich, they can easily beat Bayern Munich because compared to Manchester City, Bayern Munich is not a strong team, especially after losing the Bundesliga title to Leverkusen.
It was not the first time Ancelotti defeated a strong team like Man City. Ancelotti have proven that he is a great coach, specifically for UCL competition. He already won UCL titles 4 times, 2 trophies with AC Milan and 2 trophies with Real Madrid. Ancelotti surely knows well how to beat any team in UCL, he is an experienced and smart coach. So, I think it is not really surprising if Ancelotti could beat Guardiola.
Even if Real Madrid could beat Man City, they don't underestimate Bayern Munich. Bayern Munich is also a strong team that has great records in UCL. Real Madrid surely can defeat them but Ancelotti must be careful with a surprise made by Tuchel with Bayern Munich. Although I am not sure that Tuchel can surprise us, but Ancelotti must prepare anything to deal with Tuchel's tactics.