The Tottenham midfielder joined Fulham on loan in January while Rene Meulensteen was in charge of the Cottagers, but must now answer to Magath, who took the job on Friday.
Holtby was shipped out on loan twice by Magath at Schalke and appeared to take a swipe at his old boss when Louis van Gaal was linked with the job at Tottenham.
"I wouldn't have a problem if Van Gaal came in. After all, I've survived Felix Magath too," Holtby told Bild at the time.
But the 23-year-old played down suggestions of a rift and has vowed to play his part as Fulham attempt to drag themselves out of the drop-zone.
"I don't have any fear," said Holtby. "From my point of view, it's being hyped up right now.
"I have grown as a player and my time under Magath is already almost five years away.
"We are both in Fulham to reach one goal and that is staying up. Everything else is secondary."
Holtby admits he was left shocked by the sudden arrival of Magath and there is still uncertainty about the future of Meulensteen, with reports suggesting he was not sacked.
"At the weekend, I was in Denmark visiting my girlfriend's family," he said.
"I booked a flight for Sunday afternoon, but since the first training session under Felix Magath was scheduled on such short notice for Sunday morning, I had to return a day early.
"The news was of course a big surprise."
When asked about the confusion surrounding Meulensteen, he said: "I'm a player, that's for the people upstairs, they make the decisions. We as the players, we have to work hard. We do the talking on the pitch."