Derek Jeter and Mark Teixeira each drove in a pair of runs, and Jerry Hairston Jr. added a solo homer for the Yankees. The highest-scoring team in baseball has put up at least eight runs in four of its last five games.
Helped by a slew of double plays, Pettitte (11-6) allowed two runs and five hits over seven innings to win his third straight decision. The crisp performance came after New York pitchers had surrendered 39 runs on 52 hits over the last four games, including a 10-9 loss to the Rangers in the series opener.
It was Pettitte's 189th win in pinstripes, tying Lefty Gomez for third on the franchise list and trailing only Hall of Famers Whitey Ford (236) and Red Ruffing (231).
About the only thing that seemed to slow down the Yankees were some fluke bounces.
Alex Rodriguez came up hobbling after fouling a ball off his leg in the seventh, but remained in the game at third base for another half inning. Then in the eighth, Posada took a foul ball off his gloved hand behind the plate and immediately began shaking it. He was seen by a trainer after wandering out near the mound, and was eventually replaced by Jose Molina.
David Murphy homered and drove in both runs for the Rangers, who are desperately trying to keep pace in the playoff chase. They dropped five games behind the Los Angeles Angels in the AL West and 2 1/2 games behind the Boston Red Sox for the wild card.
Murphy's solo shot in the seventh got the Rangers within 4-2 and snapped Pettitte's streak of 49 2/3 innings without allowing a homer. He promptly fanned Elvis Andrus, the veteran left-hander's seventh strikeout of the game, and the Yankees tacked on five runs in the bottom half of the inning to put it out of reach.
Derek Holland (7-8) allowed six runs on seven hits in six-plus innings in another poor outing against New York. The 22-year-old left-hander had been 3-0 with a 1.29 ERA in his last three starts, but has allowed 12 runs in two starts against the Yankees this season.
A-Rod nearly cost New York in the first, when his error on a routine grounder helped the load the bases with one out. Pettitte bailed him out by getting a double-play, and Rodriguez reciprocated the favor by leading off the second with a single. Hideki Matsui followed with a base hit, and Posada drove a 1-1 pitch over the center-field wall for his 17th homer of the season.
The Yankees added on a run in the fourth on Hairston's homer, which could have done more damage had Robinson Cano not been picked off first moments earlier. It was Hairston's 10th of the season and second since joining the Yankees in a trade with the Cincinnati Reds.
Already trailing 9-2, the Rangers loaded the bases off Brian Bruney in the eighth, but Rodriguez started his third 5-4-3 double-play of the game and the fourth turned by the Yankees to wipe out another would-be rally.
NOTES: Rangers C Jarrod Saltalamacchia said he's still targeting Sept. 1 for his return from the DL. Saltalamacchia has thoracic outlet syndrome, causing numbness in his right (throwing) hand. … There was a moment of silence before the game for Sen. Edward Kennedy, who died late Tuesday night at 77.