Chacin (1-0) yielded six hits against the Padres after opening the season with a similar 6 2/3-inning, one-run effort against Milwaukee, which resulted in a no-decision.
San Diego starter Edinson Volquez (0-2) was saddled with the loss, surrendering four runs on nine hits over frames.
Chris Denorfia supplied the lone RBI for the Padres.
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