The Milwaukee Brewers went down quietly in the first of a key, three game series in Cincinnati, falling to the Reds 3-1 at the Great American Ballpark.  The loss drops Milwaukee to 33-40, seven and a half games behind the Central Division leading Reds.   Righthander Mat Latos dominated the contest, firing a complete game four hitter with 13 strikeouts.   Norichika Aoki produced the only Brewers run, leading off the top of the sixth inning with a solo home run to right, his fourth of the season.  Milwaukee's offense managed only two bunt singles and a Rickie Weeks double the rest of the night.  Ryan Braun struck out three times, bringing an end to his 18 game hittting streak.   Yovani Gallardo took the loss (6-6), working six innings, allowing only four hits and two runs.  Jay Bruce drove in a pair with a double in the fourth.   Cincinnati tacked on an insurance run in the 8th off relievers Kameron Loe and Manny Parra.   The Brewers will send Marco Estrada, just off the disabled list against Bronson Arroyo in game two of the series Tuesday night.