Bayern Munich will not be using Robert Lewandowski's exit as an "excuse", said manager Julian Nagelsmann, as the German champions begin their Bundesliga title defence away to Eintracht Frankfurt on Friday night. Lewandowski, 34, left Bayern this summer after eight seasons, 13 major trophies, and 344 goals, with the Polish striker joining Barcelona on a three-year deal. While the exit of a star player could have a potentially detrimental impact, Bayern have moved to replace Lewandowski with Senegalese forward Sadio Mane, signed from Liverpool, while the squad has been further strengthened by the arrivals of Dutch defender Matthijs de Ligt from Juventus, highly-rated teenage striker Mathys Tel from Rennes, and midfielder Ryan Gravenberch and full-back Noussair Mazraoui, both from Ajax. "Of course we have let a player goal who scored over 50 goals and that's something we have to compensate for," Nagelsmann told reporters on Thursday. "I believe we have improved our squad and I won't be looking for excuses and blame it on Lewadowski (leaving)." Nagelsmann, 35, was appointed Bayern manager last summer and led the club to their 10th successive Bundesliga title - his first major honour. However, a quarter-final exit in the Champions League to Villarreal and a shock 5-0 defeat to Borussia Monchengladbach in the second round of the German Cup increased the scrutiny on Nagelsmann, although he insisted he does not get affected by external noise. "The pressure is more something I place on myself," he said. "I don't read that much from the media because I'm not going to be any happier. Of course a lot gets presented. Friends always ask why there is so much pressure from the media, why it's always some sort of apocalypse. "At Bayern Munich we always want to give our best and I'm not going to be scared of that. The pressure I give myself is that we will be better and more successful than the previous year and that we play in a constant way throughout the season. "We of course want to go further in the Champions League. It always depends on luck with who we come up against. We have the goal to be successful." Bayern prepared for the new Bundesliga campaign with an impressive 5-3 victory over German Cup holders RB Leipzig in the Supercup and next take on the reigning Europa League champions. Nagelsmann is aware of the challenge posed to his team by Frankfurt, who defeated Bayern at the Allianz Arena last season, and is expecting another tough battle at the Waldstadion on Friday night. "Playing in Frakfurt is not always easy," he said. "The arena is always loud, especially after the Europa League win, they certainly have that confidence that might have dropped during the league (campaign), they've certainly built that back up. "The fans are passionate, (Oliver) Glaston is a good coach and the team is strong." While much of the focus ahead of the new season has been on Bayern's new players, teenager Jamal Musiala has already shown why he is being talked about as the next big star in Germany. The 19-year-old winger starred in the Supercup and scored the opening goal, raising expectations that he will be a key player both for Bayern and the German national team at the World Cup in Qatar later this year. However, despite the growing hype, Nagelsmann is keen for Musiala to remain grounded and focused. "I certainly gave him a lot of praise because it was deserved. I think he knows that if he doesn't keep those performances up he won't be playing any more," the Bayern manager said. "He's a nice guy and I don't think he'll fly too high. He will be an important player for us and the national team as well."