It was Hensley's second start back after a bout with the flu.
One mistake was the home run he gave up to J-J Hardy in the fourth inning.
Claudio Vargas, the leading candidate for the fifth spot in the Brewers' rotation, allowed eight baserunners in four and one-third innings but let only two score.
Milwaukee manager Ned Yost says Vargas would have been better if it weren't for the desert elements.
A routine fly ball by San Diego's Adrian Gonzalez turned into an opposite-field R-B-I double, and Brian Giles got a gift single when Brewers shortstop Hardy lost a ball in the sun.
Rickie Weeks, the Brewers' new leadoff hitter, was 1-for-3 with a stolen base as he continues adjusting to his new role. Weeks is hitting .279.