The Welshman was sacked last month on the back of a winless start to the season after 12 matches, leaving them rooted to the foot of the Premier League.
And with Redknapp revealing he had been just hours away from taking control of the Ukraine national team, Fernandes says he was desperate not to lose out on the former Tottenham boss.
"Harry is a special manager," Fernandes told www.qpr.co.uk. "If he wasn't available, I would probably have persevered with Mark, but Harry is a fantastic manager.
"I've known him for years going back to when he was at West Ham. Harry being available swung it for us.
"We're all in this together. No shirking. Let's see what Harry and the boys do. It's up to the 11 guys on the pitch to make it happen for us now.
"If we can pick up a couple of more wins before the new year, we're back to where we were this time last year. Coming off a win and three draws, there's a bit of renewed confidence about the place now."
QPR are unbeaten in four matches since Redknapp's arrival and picked up their first league win of the season against Fulham on Saturday to leave them five points from safety.
Concerning stories that Fernandes would jump ship if they suffered the drop, the Air Asia owner added: "Come what may, in May, we'll still be here.
"I'm firmly committed to the club. I'm not someone who's going to run away from things. There are still a lot of good things happening. The training ground is well on track and the stadium plans are progressing.
"We're hopeful of getting category two status in the Academy. There's no change to our off-the-field strategy. There are lots of good things going on.
"We inherited a club that needed a hell of a lot of work and we'll continue to progress with our short, medium and long term goals. I'm a strong character who has been through a hell of a lot in life.
"The aviation business isn't for those with a weak heart. But I've got to say, the run of results - before Harry came in - really affected me. It's been really tough.
"I'm the leader and it's a great shame that after so much honest effort, we are where we are in the table."
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