Stuttgart, Germany -- (Sports Network) - Seeded Argentines Agustin Calleri and Eduardo Schwank were among Tuesday's opening-round winners at the Mercedes Cup.

The sixth-seeded Calleri bested Austrian lefthander Jurgen Melzer 7-6 (7-3), 6-4, while the eighth-seeded Schwank came from behind to beat fellow Argentine and former top-five star Guillermo Coria 0-6, 6-1, 6-2 on the red clay at TC Weissenhof. The 2003 Stuttgart titlist and former French Open runner-up Coria entered the draw as a wild card this week.

Two other results saw Kazakhstanian qualifier Yuri Schukin overcome Argentine Carlos Berlocq 4-6, 7-5, 6-3 and Czech qualifier Lukas Rosol race past Austrian qualifier Martin Fischer 6-2, 6-4.

Two other bouts were suspended until Wednesday, as fifth-seeded Italian Simone Bolelli was tied with German Mischa Zverev 6-7 (6-8), 6-4 and Argentine Brian Dabul was leading German Denis Gremelmayr 6-3, 5-5 when play was called. Rain delays interrupted the play here on Day 2 and darkness ultimately forced the players off the courts.

This week's titlist will collect $185,000.