The Austrian saved all four break points he faced during the 95-minute victory.

Thiem will next face Serbia's Hamad Medjedovic, who posted a 4-6, 6-1, 6-4 victory over Zhizhen Zhang of China, the fifth seed.

Belgium's Zizou Berge notched a 6-0, 4-6, 6-3 victory over Serbian Laslo Djere, the eighth seed. Also winning matches were Germany's Daniel Altmaier, Spain's Jaume Munar and Austria's Jurij Rodionov.

Nordea Open

Luca Van Assche converted 32 of 36 first-serve points (88.9 per cent) while registering a 7-6(2), 6-4 victory over Swedish wild card Dragos Nicolae Madaras in the first round of the Nordea Open in Bastad, Sweden.

The 19-year-old Frenchman had a 3-2 edge in aces. Van Assche will face defending champion Francisco Cerundolo of Argentina in the second round on Wednesday.

Also, Brazil's Thiago Monteiro rallied for a 5-7, 6-4, 6-4 victory over Daniel Elahi Galan of Colombia. Galan had a 10-9 edge in aces.