The top-seeded Austrian, who is yet to advance beyond the quarter-finals (2013) in Vienna, fired seven aces and saved all three break points he faced to advance after one hour and 45 minutes. Bemelmans, who also reached the last eight in 2013, was aiming to record his first Top 10 victory on his eighth attempt.
Thiem improves to 7-7 at the ATP World Tour 500-level event and will meet Sam Querrey of the U.S. for a place in the quarter-finals. Querrey beat 2011 champion Jo-Wilfried Tsonga 6-3, 3-6, 6-3. Against Querrey, the 25-year-old Thiem will be searching for a 50th tour-level victory this year (49-16).
Fabio Fognini joined Thiem in the second round after notching his third victory in four FedEx ATP Head2Head meetings against Damir Dzumhur. The seventh seed, who has captured three tour-level trophies this year, prevailed 6-4, 6-3 after 71 minutes to notch his 46th victory in 66 matches this season.
Lucas Pouille is also through to the second round, keeping calm under pressure to defeat Philipp Kohlschreiber 6-4, 6-7(5), 6-4. The Frenchman earned his 25th tour-level victory of the season after two hours and 15 minutes, saving all nine break points he faced en route to victory.
Did You Know?
Thiem is one of seven players, behind Rafael Nadal (5) and Novak Djokovic (4), to win three tour-level trophies this season. The Austrian has already captured crowns this year in Buenos Aires, Lyon and St. Petersburg.