Brewers starter Jeff Suppan gave up four solo home runs.
The game was played in front of a second straight sellout crowd of 12,000 at Scottsdale Stadium, including commissioner Bud Selig, a former owner of the Brewers.
On Dec. 4, Zaun signed as a free agent with the Brewers. They are his ninth team, and it has been a good fit thus far.
"I like it here. We have a great mix of young guys and veteran guys," Zaun said. "That's what you need. We have guys like Soupy (Suppan), myself, Jim Edmonds, Craig Counsell, with Hoffy (Trevor Hoffman) taking care of the bullpen."
Zaun is 8 for 19 (.421) with a home run and his eight RBIs are tied for the team lead, matching shortstop Alcides Escobar.
"I'm very comfortable with my swing," said Zaun, a switch-hitter.
He attributes the consistency to some changes in his hitting approach that he implemented in May of last season and said he had a better second half, which he split between Baltimore and Tampa Bay.
"I continued to do it when I started swinging again in the offseason. I want to make my swing as simple as possible," Zaun said.
It is possible that Zaun could catch at least 100 games, and that means remaining healthy.
"I take a lot better care of myself now than when I was 28," he said. "Sometimes you take that stuff for granted when you're young. I'm a little smarter now."
Suppan is coming off a season in which he finished 7-12 in 30 starts, the 11th straight season in which he started that many games. He also spent nearly a month on the disabled list with a strained left oblique.
Suppan won't refrain from throwing a higher strike if he feels it is necessary.
"I'm not saying I'm going to throw four-seamers (fastballs) up all the time, but you do have to change up on the eye level," Suppan said.
He threw a lot from the stretch against the Giants. When he threw from the stretch in a previous game against the Chicago Cubs, he said he did not feel comfortable, but he felt more so on Sunday.
"I am trying to build on the spring, working on the curveball and changing speeds," he said.
Giants starter Jonathan Sanchez entered the game without allowing any runs in five innings. On Sunday, he gave up six earned runs and three hits with five walks in two innings.
Brewers reliever Chris Smith entered the game with two outs in the seventh inning and picked off Buster Posey at first base without throwing a pitch. He also pitched a scoreless eighth. ... The Giants play split-squad night games on the road against Texas and San Diego on Monday. ... Rowand has been scratched from the game against the Padres in order to rest a strained quadriceps. ... Infielders Edgar Renteria and Juan Uribe also will get the night off.