“I’m bitterly disappointed,” Redknapp told QPR's official website. “We were poor, really, really poor. You’ve got to have quality in any competition and we didn’t have any tonight.
“Fair play to Burton, they were excellent. Gary’s done a great job here and they were good value for the win.”
However, new signing Leroy Fer has backed the 67-year-old to get the best out of the Rs.
“Of course he has the full backing of the squad,” Fer told reporters. “He’s a great manager and a great coach. We have to believe that things will turn around.
“There is no crisis. We’ve played three games and lost three games. We’re out of the cup, but we need to crack on. You can’t blame people, you have to stay in the team, look at what went wrong and look forwards to the next game.”
Ross McCormack has targeted a win for Fulham against his former side Cardiff City on Saturday.
The £11 million striker, signed from Leeds United this summer, says it was 'nice' to beat Brentford in the Capital One Cup but insists his team must concentrate on the Championship.
“Cup wins are nice but your bread and butter is the league," McCormack told reporters.
“We’ve had a bad start so it’s important we put it right, starting Saturday.
“We’re four games in, we’ve got a completely new squad, we’re trying to gel, we’re trying every day in training to gel.
“Maybe a result away from home in a local derby will give us the belief we’ve been needing to go on.”