It was his 23rd career game of at least 10 strikeouts.
"When he's throwing that hard," said manager Bob Melvin, "you better guess right."
From the start, Kazmir was consistently hitting 94 mph, a tick or two above his average velocity.
"Felt like everything was working well to where I could really pump it up if I needed to and still be under control," he said. "That's what I did today, and it was earlier than I thought. It felt good early on, and as soon as I saw I was getting on the fastball, I stuck with it."
After the A's provided him five runs in a lengthy third inning, Kazmir experienced back tightness in the fourth, leading to a visit from a team trainer. Kazmir walked his next batter, prompting more speculation, but came back to strike out Ryan Rua on three pitches.
Kazmir went straight for the clubhouse to stretch out his back and returned to even more runs.
"I'll take that any day," he said.
Jane Lee is a reporter for MLB.com. Read her blog, Major Lee-ague, and follow her on Twitter @JaneMLB. This story was not subject to the approval of Major League Baseball or its clubs.