ARLINGTON, Texas -- Craig Gentry thought he ended a rally in the eighth inning.
Instead, the speedy outfielder who came into the game as a late replacement became the latest star for the streaking Texas Rangers.
Oakland left fielder Yoenis Cespedes appeared to misjudge Gentry's deep fly ball with two outs in the eighth. Cespedes took a couple of steps in at first and then sprinted back toward the wall, but the ball easily sailed over his head.
"I knew I hit it decent," said Gentry, who came in as a pinch hitter for David Murphy in the seventh. "But to be honest, I thought he was going to catch it."
On a 3-2 pitch, Cruz walked to force in Andrus and cut Oakland's lead to 2-1. Ryan Cook, who had allowed opponents to hit just .102 against him, replaced Balfour and gave up Gentry's game-deciding hit.
The Rangers, who own baseball's best record at 49-29, have won four in a row and 16 of 20 since June 8. They've done this despite having three starting pitchers and two key relievers on the disabled list.
"We weren't hitting the ball that hard early," Rangers manager Ron Washington said. "But we kept grinding and kept grinding. That's why you play nine innings."
Harrison (11-3) threw a season-high 121 pitches and allowed two runs and eight hits to win his seventh consecutive decision. The left-hander joined Tampa Bay's David Price as the American League's only 11-game winners.
Harrison is making a push for his first All-Star game appearance two days before the teams are announced. He improved to 5-0 with a 1.29 ERA in six June starts.
"I was fortunate to stay in there long enough to keep us in the game," Harrison said. "I was excited. I can't imagine how Gentry was feeling."
Cespedes was 2 for 4 and improved to 12 for 20 this season against Texas. He drove in Oakland's first run with an RBI single in the fourth.
The Cuban outfielder, though, had a tough time on Gentry's triple. A's manager Bob Melvin couldn't definitely say if Cespedes misjudged the play.
"It looked like he broke in," Melvin said. "I'm not 100 percent sure from my angle. I probably need to look at video."
Oakland rookie A.J. Griffin made his second career start allowed two hits in six shutout innings.
Griffin threw 67 of his 105 pitches for strikes and retired 13 in a row at one point before Hamilton's bloop single in the sixth.
Griffin struck out four and walked two against baseball's top-scoring team. The 24-year-old pitched six innings in his big league debut Sunday against San Francisco. Hamilton and Cruz had the only hits off Griffin, who started the season pitching for Double-A Midland.
"They shut us down the whole game," Gentry said. "We were able to get something going in the eighth inning."
"Mike Adams and Joe Nathan needed time down." Washington said. "They needed a break."
Matt Hicks will join the Rangers radio broadcast team Saturday on a temporary basis. Steve Busby has moved from radio to television broadcasts while play-by-play announcer Dave Barnett is out with what he called "complicated migraines." Barnett has been off the air since June 18 when he gave a rambling, incoherent description that confused viewers. Hicks called games for the Corpus Christi Hooks, the Double-A affiliate for the Houston Astros, since 2004. ... Carter was recalled from Triple-A Sacramento on Friday. ... Balfour's streak of 11 2/3 consecutive scoreless innings over 10 games ended.