The 32nd-ranked Hanescu broke four times and will play Marcel Granollers of Spain, who defeated Teimuraz Gabahsvili of Russia 7-6 (11), 6-3.
Seventh-seeded Mikhail Youzhny of Russia defeated Daniel Gimeno-Traver of Spain 6-2, 7-6 (7).
German wild card Andreas Beck rallied to beat Jan Hernych of the Czech Republic 5-7, 6-3, 7-5, while Nicolas Massu of Chile defeated Robin Vik of the Czech Republic 6-4, 6-2.
Also advancing to the second round was Daniel Koellerer of Austria, who downed Thomaz Bellucci of Brazil 6-4, 6-4.
Agustin Calleri of Argentina, who won the event in 2006, reached the second round after Yen-hsun Lu of Taiwan quit the match due to illness at 3-6, 7-5, 0-1.
The Austrian Open, a warmup event for next week's French Open, was initially scheduled for July but moved to May after the Hypo Group tournament in Poertschach, Austria, was dropped from the ATP Tour calendar.
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