Hungary's Marton Fucsovics battled through to the second round of the BMW Open in Munich by beating Italian qualifier Lorenzo Sonego in three sets.
Eighth seed Fucsovics prevailed on his fourth match point after saving nine of 14 break points in the match to win 7-5 4-6 7-6 (8).
He will now play Germany's Jan-Lennard Struff or Brazilian qualifier Thiago Monteiro.
In the only other main-draw match on a rain-affected opening day, Japan's Taro Daniel beat France's Ugo Humbert 6-4 6-4.
At the Estoril Open in Portugal, Australian sixth seed Alex de Minaur lost his first-round match against Portuguese qualifier Joao Domingues 2-6 6-2 2-6.
World number 97 Guido Andreozzi, of Argentina, beat Bolivia's Hugo Dellien 6-3 6-3, while Japan's Yoshihito Nishioka and American Reilly Opelka also progressed.
