Charlie Austin struck twice as Burnley picked up their first win of the season and ended Derby's perfect start.
Austin hit the post with a first half header before finding the net four minutes after the break.
Rams' substitute Theo Robinson levelled in the 71st minute but Austin scored his fifth goal of the campaign three minutes later to seal the victory.
It was Burnley's first league win in seven matches, with the last coming at Pride Park in the 2010/11 campaign.
Burnley boss Eddie Howe recalled long-serving goalkeeper Brian Jensen for his first start of the season in place of former Derby stopper Lee Grant and he was quickly into action making a fine save to keep out a powerful header from Jason Shackell.
Keith Treacy and Ross Wallace fired over before Burnley almost stole a half-time lead but Austin's header came back off the woodwork.
He finally found the net in the 49th minute when Treacy cut the ball back from the byline and Austin steadied himself before firing past Frank Fielding from six yards out.
Nigel Clough's side almost equalised through Ben Davies when he clipped a shot past Jensen but Ben Mee got back to clear the ball off the line.
Burnley hit the woodwork again when Treacy smashed against the bar from 12 yards out before Derby equalised in the 71st minute, Robinson poking home John Brayford's driven cross from close range.
However, the Rams were not level for long.
Former Blackburn keeper Fielding failed to clear Wallace's shot and Austin capitalised with his second of the game.
Derby's Craig Bryson went close with three efforts - the best forcing a fingertip save from Jensen - but Burnley held on for the three points.