The West London side are staring relegation in the face, seven points from safety with eight league games to play after Saturday's 3-2 defeat thanks to Christian Benteke's late winner for the hosts.
"In any business there will be hiccups. But this is not a one-year or two-year project. This is a lifelong commitment," Fernandes said in an open letter on the club website on Monday.
"There are still eight games to go. We beat Chelsea at Stamford Bridge and showed against Southampton and Sunderland that we are capable of putting wins together.
"And we have scored seven goals in our last three fixtures, so anything can happen.
"We fight and we fight. I am not despondent at all. QPR has come a long, long way from where we were, and the plan continues," said Fernandes, the chief executive of Malaysia's Air Asia who became majority shareholder at the club in 2011.
QPR's debts have increased to almost 89 million pounds, according to the latest financial results which cover the 2011/12 season, published earlier this month.
Manager Harry Redknapp spent more than 20 million pounds on players in the January transfer window and half of the club's four wins this season came in the two matches prior to the Villa game, raising supporters' hopes of avoiding relegation.
"We inherited a club that lacked so many things, and we are rebuilding every aspect. That's a huge challenge," said Malaysian Fernandes.
"We need a new training ground, a new stadium, a more successful academy. That's so exciting. How can anyone feel down for too long?
"Forget Aston Villa. Focus on the future. The path in front of us is exciting," he said.
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