With eight games remaining, the Premier League's bottom club are seven points from safety after they "threw away" victory at their relegation rivals, according to Redknapp.
"It's a setback but we can't go feeling sorry for ourselves," he told QPR's website. "We've got to keep going.
"There are still games to go. If we keep playing well we can win four of five games."
"I'm upset for the lads, I thought they played well today," he said.
"We've not lost through a lack of effort. We were fantastic in the first half. It was so one-sided it was unbelievable.
"I wanted to come in [at half-time] 1-0 up, even though it could have been more. Instead they've suddenly got a lift after being awful.
"They couldn't believe their luck. We threw it away from where we were."
"We've been playing well for a number of weeks now," Lambert told the BBC. "There's a long way to go. This is the first time this football club has won back-to-back games since 2011.
"It's an incredible stat. But the noise of the stadium, the crowd with us, we are certainly playing well enough."
