The victory in Game 3 gave the Phillies a 2-1 lead in the World Series, with Game 4 set for Sunday night in Philadelphia.
Bruntlett led off the inning, going to first when J.P. Howell hit him with a pitch. Bruntlett took second on a wild pitch and then went to third when Rays catcher Dioner Navarro threw the ball wildly into center field.
After intentional walks to Shane Victorino and pinch-hitter Greg Dobbs, Ruiz hit a weak grounder toward third and Bruntlett scored the winning run as Evan Longoria flipped the ball over Navarro's head.
The game was delayed for 1 1/2 hours by rain and took more than three hours to complete, with the winning run crossing the plate just before 2 a.m. EDT.
Ruiz, Chase Utley and Ryan Howard homered for Philadelphia. Gabe Gross had two RBI for Tampa Bay.
J.C. Romero (1-0) got the victory after pitching 1 1/3 innings in relief.
Howell (0-1) took the loss in one inning of relief.