Sepp Blatter claims an investigation into him by the Swiss attorney general is "outrageous" and insists there is no evidence of wrongdoing.
Proceedings were opened against the FIFA president last month, and he was questioned on suspicion of criminal mismanagement and misappropriation of FIFA funds.
Swiss authorities said that UEFA president Michel Platini was also being questioned as a witness over "a disloyal payment'' of 2 million Swiss francs from Blatter in 2011 -- for work done between 1999 and 2002. It is also alleged that Blatter manipulated FIFA contracts, including one in 2005 with then-Caribbean Football Union president Jack Warner.
But Blatter, who returned to work at FIFA HQ this week, told German magazine Bunte he has no case to answer.
"The situation is not pleasant," Blatter said. "I am being condemned without there being any evidence for wrongdoing on my part. That is really outrageous.
"This is just an investigation, not an indictment. I'm dealing with it and I'm co-operating with the authorities.
"I'm feeling good. I'll survive it. FIFA is still functioning well and the selected president remains in office.
"I will fight until Feb. 26 [FIFA presidential election date]. For myself. For FIFA. I am convinced that evil will come to light and good will prevail."
Blatter is continuing as president until he is due to stand down at the election in February, though four leading FIFA sponsors have called on him to quit with immediate effect.
But Blatter even brushed those demands aside by saying only American companies had turned against him.
"That's only the Americans," added Blatter. "Adidas in Germany, Gazprom in Russia and Hyundai and Kia in South Korea are still backing me."
He also denied speculation that he could still stand for re-election again next year.
"I assure you that I will stop on Feb. 26, 2016," he added. "That's definitely the end. But not a day sooner. By then we'll have found a really good candidate who'll make a great new president."