Argentine second seed Juan Monaco became the first man into the semi-final hat at the Stuttgart claycourt tournament on Friday after beating Slovakian qualifier Pavol Cernevak 6-1, 7-5. Monaco, the world number 14, will next meet either German invite Dustin Brown or Spaniard Guillermo Garcia-Lopez. The 28-year-old right-hander from Buenos Aires bagged three breaks of serve in the opening set and then, having trailed 0-4 in the second, turned things around with four more breaks to polish off his rival in 1hr 36min. Monaco is chasing his third trophy of the season and seventh of his career after wins at Vina del Mar in Chile in January and then Houston in April, both on clay.