Melzer, playing in the city of his birth, recorded a vital break when Haider-Maurer was serving for the championship in the second set, setting off a rally for a 6-7 (10-12), 7-6 (7-4), 6-4 win. It was Melzer's third career title. In addition to the 2009 Bank Austria championship, he won an event in 2006.
Haider-Maurer was an unlikely finals opponent. He is ranked No. 157 and only entered the field when Ernests Gulbis dropped out for personal reasons. Haider-Maurer was just 2-6 in career ATP-level matches before running off four wins to get to Sunday's final.
But he pushed Melzer, No. 12 in the world, to the edge, winning the lengthy first-set tie-breaker and going up 5-4 in the second set. Melzer broke back and evened the set and took the final four points of the tie-breaker to even the match.
Melzer grabbed the three-set lead with a break -- only his second of the day -- in the seventh game and held serve the rest of the way.
Melzer collected $145,000 for the win while second place was worth $76,400 for Haider-Maurer.