The London club have secured just four points from their first seven Premier League games this season after winning the Championship play-off final to make an immediate return to the top flight.
Rangers were beaten 2-0 by West Ham on Sunday and are bottom of the table heading into the international break.
Fernandes sacked Mark Hughes after a dreadful start to the season almost two years ago, but the QPR supremo is not planning to part company with current boss Harry Redknapp.
And the Malaysian businessman hit back at his critics on Twitter following the club's latest defeat.
He tweeted on Monday: "A couple of things, we got promoted. Please note where other clubs who got relegates [sic] are .pls [sic] remember how many clubs got straight up.
"We have always been on the backfoot with players. We had so many loans last year as we cleared out.
"That's it. There should be no more excuses from anyone especially me, buck stops at me. I'm up for the battle.
"Is sacking the answer. When we met [let] mark hughes go we still went down. Is it tactics, is it players, is it coaching, is it fitness."
Fernandes also revealed that he did all he could to keep Loic Remy at the club before the France striker joined Chelsea just before the transfer deadline.
"When we lost Remy 48 hours before deadline day it was huge huge blow. Huge blow. But we fight on. Stop sendind [sic] me ridiculous tweets," he added.
"I'm not stupid or a quitter. All I can assure fans is as always we will be transparent and leave no stone unturned to stay up and build.
"I love the Remy comments. Remy was staying, he was in my house for dinner to sign the extension. Then Chelsea called. What back up pls [sic].
"Yeah I can pull out a striker in 24 hours. We tried hard with [Fabio] Borini. So pls [sic] tell me me what you would have done. Dammed easy to be armchair critics."
Fernandes described the 2-0 defeat at Upton Park as "just not good enough" on Sunday, but insisted a lack of effort from the players was not behind their latest setback.
"I don't think the players didn't try," he tweeted on Monday.
"Look at the stats. The [opening] goal was never a goal, took the wind out of us. The second goal was against the run of play. No excuses. We still should ha e dine [have done] better."
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