OAKLAND, Calif. -- Aaron Cook is enjoying one of the most productive stretches of his career. It's also Colorado's best stretch since ending the 2007 season on a tear.
"Even when other teams get one or two hits, he's always one pitch away from putting the inning down," Rockies manager Jim Tracy said. "That's the mind-set of a pro, the mind-set of a stalwart, front end of the rotation guy."
Cook has a 1.75 ERA over his past five games, and with the Rockies averaging more than 6½ runs during that stretch, the combination has proved effective. The Rockies have won 20 of their past 23 games, and improved to 22-7 under Tracy.
"This is one of those games where we did some things to get some runs, and Aaron Cook made the ones we did get, stand up," Tracy said. "He was fantastic. I felt like he got better as the game went on."
• A's: Ellis activated
Cook (8-3) gave up nine hits while walking one and striking out four. The Rockies' franchise wins leader (60) had a 12-inning scoreless streak against the A's end.
"Unfortunately I've had a lot of practice with guys on base," Cook said. "But I'm comfortable because I work on it a lot. It's not something that fazes me like it used to. I'm able to slow down the game and still execute pitches."
Former A's closer Huston Street earned his 19th save in 20 chances by getting the final three outs. He saved all three games of the series.
"The way we're playing, and the way the A's were playing, this was a big series for us," Street said.
A's starter Vin Mazzaro (2-3) gave up three runs on five hits in five-plus innings. He walked four and struck out eight in losing his third straight, all in interleague play.
"I thought he did a pretty good job of holding a pretty good hitting club," A's manager Bob Geren said. "He's one of the best young pitchers in the league."
The A's finished 5-13 in interleague play, their worst performance against the National League. The Rockies matched their best record (11-4) in interleague play.
"They put together some good at bats against us the entire series," Geren said. "The big difference was the extra base hits. We haven't hit the long ball. Against a sinker ball pitcher like Cook it's not easy."
Jason Giambi's average dipped below .200 briefly before his eighth-inning single snapped a 1-for-19 streak and bumped his mark to .203, still the lowest in the AL.
The Rockies scored twice in the second inning on Iannetta's RBI forceout and Smith's run-scoring double. Gonzalez added an RBI double in the sixth.
Kurt Suzuki's single to open the ninth ended Cook's outing. Street gave up singles to Cabrera and Sweeney before striking out pinch-hitter Nomar Garciaparra and Mark Ellis and getting Adam Kennedy to fly out to left.
"We hit a lot of balls hard but we also wasted some opportunities," A's outfielder Jack Cust said.
- Mazzaro failed to finish the sixth inning for the first time in his career.
- Cabrera extended his hitting streak to 11 games.
- Smith's double gave him a career-high six-game hitting streak.
- Ellis returned to the lineup after missing the past 55 games.
- A's 1B Daric Barton was optioned to Sacramento of the Pacific Coast League to make room for Ellis.
- Rockies 1B Todd Helton recorded his second triple of the year and the 33rd of his career.
- A's starting pitchers are 0-5 with a 7.61 ERA during the past five games.