PHOENIX >> Tony Watson was acquired at the non-waiver trade deadline last week because the Dodgers needed a lefty reliever who could come in and retire dangerous left-handed hitters like Jake Lamb.Maybe they still do.Lamb hit a grand slam off Watson in the seventh inning Tuesday night - his second home run of the game - as the Arizona Diamondbacks came from behind to beat the Dodgers, 6-3, in the opener of a three-game series between potential playoff opponents.