It easily marked Mazzaro's most impressive start to date this season, which has seen him steadily build up his arm strength while once again getting acclimated to Oakland's rotation in place of the injured Brett Anderson.
"Mazzaro was tough," Cleveland manager Manny Acta said. "We couldn't get anything going against him. He had a good fastball and a good slider."
The 7 1/3 innings marked a career high for Mazzaro, whose seven strikeouts represented a season high. He compiled four 1-2-3 innings in the winning effort -- his fourth victory of the year -- and was pulled following 111 pitches and a one-out double to Jayson Nix in the eighth.
"Going into the eighth inning," Mazzaro said, "I felt strong. I felt good. I could've gone more, but you bring in the bullpen and you know they're going to shut it down."
They did just that, as Jerry Blevins stranded Nix at second by garnering two quick outs, which set up another Andrew Bailey save -- his 17th of the season -- in the ninth, when the A's closer boarded Jhonny Peralta on a single with one out before forcing Matt LaPorta to ground into a double play and end the rather quick affair.
Mazzaro has now pitched through the sixth inning in four of his last five starts, Sunday's performance resulting in what manager Bob Geren deemed "better than any of his starts."
"I know his last outing you see the same numbers," the A's skipper said, "but he wasn't throwing many strikes then. He threw a lot better today. He got better as the game went on. I think he found command of both of his pitches and was pretty unhittable there for awhile."
"I'm definitely feeling more comfortable," Mazzaro said. "I'm cutting down on the walks and getting groundballs when I need to. And the guys behind me are making great plays. Good stuff is happening."
One of the several defensive gems Sunday came from Adam Rosales, who took away a line drive hit to add to an already impressive day witnessed by his parents and girlfriend, Callie, in the stands.
The A's infielder, getting a start at third base in an effort to hand the struggling Kevin Kouzmanoff a day off, enjoyed a 2-for-4 day at the plate, where he picked up his sixth homer of the season with a shot to left in the seventh off Tribe starter Fausto Carmona, also invited to the Midsummer Classic on Sunday.
"My girlfriend and her family grew up Indians fans," Rosales said with a smile, "so it was just fun to have them here all weekend.
"The home run, it was a fastball more in on the plate. [Carmona] comes right after you, so you have to take advantage of every opportunity."
Rosales' long ball represented the A's third run of the day, which began with Oakland quickly ahead 1-0 thanks to a first-inning RBI groundout from Ryan Sweeney. The A's outfielder brought home Coco Crisp, who eventually exited the game in the second due to ligament pain near his hamstring and groin area.
An RBI base hit off the bat of Mark Ellis in the fourth frame gave the A's two runs compared to the Tribe's one, scored in the third on a run-scoring single from Austin Kearns.
The A's, who took the first and last games of the three-game set in Cleveland and finished their two-city road trip 4-2, have now won seven of their last eight contests following a stretch in which they lost 10 of 12. They return home Monday to kick off a six-game homestand against the Yankees and Angels.
"This trip was huge for us," Rosales said. "Momentum is everything for us, for any team. It definitely gives us confidence heading into this week for the Yankees series. Our pitching's been great, so with our pitching and defense, we'll be solid."