Cahill scattered six hits over 5 2/3 innings to win his fourth consecutive decision and received plenty of support from his teammates, who stayed on a roll offensively in a 9-1 victory over the Texas Rangers on Tuesday night.
"It's one of those goals you set at the beginning of the year," Cahill said of his 10 wins, three of which have come against the Rangers. "I've gotten lucky and had I've had my good stuff two or three times against them. Tonight I didn't have my best stuff but kind of got lucky, got some double plays when guys were on. Sometimes it just works out that way."
Kurt Suzuki and Daric Barton drove in two runs apiece for Oakland, which had 12 hits against five pitchers. Five players had two hits each as the A's clinched their first winning month in more than a year.
Texas' loss kept the Rangers 6½ games behind Boston in the AL Wild card and it clinched a postseason berth for the New York Yankees.
"They are a pretty good young team and they finally put it together," Texas manager Ron Washington said of his former team, the A's. "Their pitching staff is young and those kids have gotten their feet wet and they are showing their ability that they have."
Oakland improved to 14-6 in September, tied with Colorado for the best record in the majors. It's the first time since June 2008 the A's have had a winning record in a month.
Suzuki hit a two-run double and scored on Barton's RBI single during a five-run seventh when the A's broke the game open to win for the 10th time in 12 games.
Barton had two hits and is batting .393 (11 for 28) over his last nine games.
"Daric really the last couple of weeks has been our hottest hitter, quietly doing it because there hasn't been the big homer or whatever," Oakland manager Bob Geren said. "But if you're looking for the most consistent guy for the last 15-20 days, he's been the guy."
Texas carried a four-game road winning streak into the game and had scored at least 10 runs in each of the four victories, one shy of the major league record. But the Rangers weren't able to get much going against Cahill.
In addition to extending his career-best winning streak to four games, Cahill improved to 3-1 against the Rangers and hasn't lost to any team since falling to Baltimore on Aug. 11.
The A's right-hander became Oakland's second 10-game winner this season. Cahill (10-12) retired the first seven batters and received some help from Oakland's defense, which turned double plays in three straight innings and four overall.
Jack Cust walked with one out in the fifth and scored when Nelson Cruz misplayed Barton's sinking liner into a triple. Barton was running to third when the relay throw home from Texas second baseman Ian Kinsler skipped past catcher Rodriguez for an error, so Barton kept going and scored to make it 2-0.
The A's added another run in the fourth on Barton's RBI single then broke it open in the seventh with five consecutive hits and six overall. Rajai Davis had an RBI single to start the inning, Suzuki and Cust added run-scoring doubles and Mark Ellis also knocked in a run to give the A's a seven-run lead.
Texas starter Brandon McCarthy (7-4) pitched effectively but lost for only the second time in his last six decisions. Both losses have come against Oakland, which has won eight of the last 10 games between the teams.
The Rangers' right-hander gave up five hits but was done in by Kinsler's throwing error in the second and by Texas' offense which went 1 for 7 with runners in scoring position.
"I should have done a better job backing up bases," McCarthy said. "I have to be a little better than I was tonight."
- Oakland is 5-1 on its current homestand.
- The A's won despite leadoff hitter Adam Kennedy getting ejected in the first inning for arguing with home plate umpire Eric Cooper after being called out on strikes. It was the fifth ejection of Kennedy's career, his first since 2006.
- Texas rookie SS Elvis Andrus went 1 for 4 and is batting .298 over his last 51 games.