In a game that made up a rainout earlier in the season, Texas won its fourth straight with Yu Darvish striking out 14 over seven shutout innings.
The Rangers, whose season appeared on the verge of collapse when the week began, produced three consecutive walkoff victories over the Los Angeles Angels and have moved within 3 1/2 games of Oakland for the lead in the American League West.
Texas now travels to Oakland for a three-game series that begins Friday.
Pierzynski, Mitch Moreland and David Murphy all hit solo homers in the second, third and fourth innings. Leonys Martin added a two-run double in the fourth and Pierzynski had a two-run single in the seventh. Pierzynski also had his first stolen base of the year.
Darvish (10-5) gave up five hits without a walk in 100-degree temperatures.
Zeke Spruill was called up from Class AAA Reno to make the start and lost his first major league decision. He gave up five runs on seven hits in four innings.