AC Milan s Swiss forward #17 Noah Okafor (C) celebrates with teammates at the end of the Italian Serie A football match between AC Milan and Lazio at the San Siro Stadium in Milan on September 30, 2023. AFP
Dortmund suffered a disappointing 2-0 loss away at Paris Saint-Germain in the first round of the Champions League, but they have developed a winning habit in the Bundesliga in 2023, losing once in 25 league games.
That one loss however was a defeat at Bayern in April which ultimately helped cost them the title.
Fuellkrug said he "dislikes the perception" that Dortmund are struggling.
"We have won our last three games and are unbeaten in the league for half a year, so in terms of our play it can't be that bad."
Dortmund drew 2-2 at home with lowly Mainz on the final day of the 2022-23 league season, which handed Bayern an 11th straight league title.
Manager Edin Terzic said the quality of Dortmund's group opponents PSG, Milan and Newcastle made home wins even more important.
"As a rule, you need around 10 points in the group (to qualify). If you break that down, you know just how important the home games are."
Terzic said Dortmund would "be more courageous" than against PSG, explaining "we've done a lot of good things in the last few games, which will be important again tomorrow."
Milan sit second in Serie A on goal difference behind city rivals Inter, having drawn their first Champions League group game 0-0 at home against Newcastle.
Terzic said Milan are "very dangerous", pointing to ex-Dortmund player Christian Pulisic, "who we know very well."
Fuellkrug, who moved from Werder Bremen in August, scored his first goal for Dortmund in the 3-1 win over Hoffenheim on Friday.
The striker, who will play his first Champions League home game in front of Dortmund's famous yellow wall on Wednesday, said "the boys told me that it might be a little bit more special than the Bundesliga".
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