Belgian Tom Boonen of Quick Step retained the overall leader's golden jersey after placing sixth on the day.
Haussler, 26, was delighted after coming through the 135km stage - but stage one winner Boonen himself endured a rough time of it heading for the finish.
He explained: "Two of my teammates who were supposed to launch my sprint, Nikolas Maes and Andreas Stauff, suffered punctures in the final five kilometres and, badly positioned, I was unable to go for it. It's a shame as the rest of the day was perfect."
Italian champion Giovanni Visconti launched an early escape with compatriot Manuel Quinziato, Russian Mikhail Ignatyev and Belgians Niko Eeckhout and Jan Ghyselink at the 7km mark.
But after putting 5min between themselves and the pack they were finally hauled in 10km from the line.
"That's why our win was deserved," said Haussler, whose 2010 season was ravaged by knee problems.
"We were working away whereas Quick Step were watching us do so."
Wednesday is a 150.5km ride from Al Wakra to Messayed.
Stage 2 Results:
1. Heinrich Haussler, Australia, Garmin-Cervelo, 3 hours, 4 minutes, 3 seconds
2. Daniele Bennati, Italy, Leopard Trek, same time
3. Denis Galimzyanov, Russia, Katusha, same time
4. Theo Bos, Netherlands, Rabobank, same time
5. Roger Kluge, Germany, Skil-Shimano, same time
6. Tom Boonen, Belgium, Quickstep, same time
7. Mirco Lorenzetto, Italy, Astana, same time
8. Danilo Hondo, Germany, Lampre-ISD, same time
9. Gert Steegmans, Belgium, Quickstep, same time
10. Wouter Weylandt, Belgium, Leopard Trek, same time
11. Matteo Pelucchi, Italy, Geox-TMC, same time
12. Mark Cavendish, Britain, HTC-Highroad, same time
13. Roger Hammond, Britain, Garmin-Cervelo, same time
14. Mark Renshaw, Australia, HTC-Highroad, same time
15. Francesco Chicchi, Italy, Quickstep, same time
16. Greg Van Avermaet, Belgium, BMC Racing, same time
17. Michael Van Staeyen, Belgium, Topsport Vlaanderen-Mercator, same time
18. Russell Downing, Britain, Sky, same time
19. Frederique Robert, Belgium, Quickstep, same time
20. Gediminas Bagdonas, Lithuania, An Post-Sean Kelly, same time
General Classification:
1. Tom Boonen, Belgium, Quickstep, 6 hours, 6 minutes, 35 seconds
2. Heinrich Haussler, Australia, Garmin-Cervelo, 1 second behind
3. Mark Renshaw, Australia, HTC-Highroad, 4 seconds
4. Fabian Cancellara, Switzerland, Leopard Trek, 8 seconds
5. Juan Antonio Flecha Giannoni, Spain, Sky, 9 seconds
6. Daniele Bennati, Italy, Leopard Trek, 10 seconds
7. Andreas Klier, Germany, Garmin-Cervelo, 16 seconds
8. Gert Steegmans, Belgium, Quickstep, 17 seconds
9. Jeremy Hunt, Britain, Sky, 19 seconds
10. Dominique Rollin, Canada, FDJ, 19 seconds
11. Gabriel Rasch, Norway, Garmin-Cervelo, 20 seconds
(tie) Stuart O'Grady, Australia, Leopard Trek, 20 seconds
13. Roger Hammond, Britain, Garmin-Cervelo, 21 seconds
14. Marcus Burghardt, Germany, BMC Racing, 28 seconds
15. Bernhard Eisel, Austria, HTC-Highroad, 40 seconds
16. Graeme Brown, Australia, Rabobank, 46 seconds
17. Nikolas Maes, Belgium, Quickstep, 53 seconds
18. Johan Van Summeren, Belgium, Garmin-Cervelo, 58 seconds
19. Maarten Wynants, Belgium, Rabobank, 5:13
20. Roger Kluge, Germany, Skil-Shimano, 5:14
Haussler sprints to stage win
Doha - Australia's Heinrich Haussler of Garmin won the second stage of the Tour of Qatar on Tuesday between the Camel Race Track and Doha Golf Club, ousting Italian Daniele Bennati and Russian Denis Galimzyanov in a sprint finish.