ST. PETERSBURG, Fla. (AP) -With one big swing, Josh Hamilton put his old team away.

The one-time Tampa Bay prospect hit a grand slam and matched his career high with five RBIs, helping Vicente Padilla and the Texas Rangers cool off the AL East-leading Rays 12-6 on Tuesday night.

Hamilton, the former No. 1 overall pick in the draft whose career with the Rays was derailed by drug addiction and injuries, had an RBI double off Andy Sonnanstine (6-3) in the first. The Rangers avoided a possible late-inning collapse when he added his second grand slam of the season in the eighth off J.P. Howell.

''It felt good ... especially in that situation,'' Hamilton said. ''This is where I started, and it's my first home run here.''

The five RBIs matched a career best set May 16 against Houston and boosted Hamilton's season total to a major league-leading 58. He's also batting .329 with 13 homers after hitting 19 with Cincinnati in 2007, his first season in the bigs.

The 27-year-old outfielder, 0-for-4 Monday in his first game against his old team, is 4-for-6 and has driven in 14 runs with the bases loaded this year.

To hear him, though, his first-pitch homer off a sinker was pure luck.

''I've never been more frustrated after hitting a grand slam in my life,'' Hamilton said. ''I was having so much trouble picking the ball up. When I made contact, I actually closed my eyes for a spilt-second because I thought (the ball) was going to run on me, that it was going to hit me.''

Padilla (7-2) allowed five runs and seven hits in six innings to win his fifth straight decision and stop Tampa Bay's four-game winning streak. The right-hander walked four and struck out a season-high 10.

Brandon Boggs had an RBI single in the first and a two-run double in the second, when the Rangers scored five unearned runs off Sonnanstine to build a 7-0 lead that Padilla was barely able to protect.

Cliff Floyd and Eric Hinske hit two-run homers for Tampa Bay, which cut its deficit to 7-5 when Padilla got Hinske to ground into a double play in the sixth. Hamilton broke the game open after Ian Kinsler 's RBI single put Texas up 8-5 in the eighth.

''In the seventh inning, I had a good feeling,'' Rays third baseman Evan Longoria said. ''We hung around long enough. We were going to give ourselves a chance to win the game. Unfortunately, Hamilton comes up with a big hit like he's been doing and kind of put us away.''

Tampa Bay began the night with the best record in the majors, leading Boston by a half-game in the AL East.

The loss was the second straight for Sonnanstine, who had won five straight decisions before struggling in an outing last week at Oakland. The Rangers were 6-for-12 with runners in scoring position in the first two innings.

The Rays had gone eight games without an error, two shy of the franchise record, before Longoria mishandled Hamilton's grounder, allowing the first of five runs the Rangers scored with two outs in the second.

Milton Bradley and David Murphy followed with RBI singles off Sonnanstine before Boggs added his two-run double to make it 7-0.

Floyd cut into Tampa Bay's deficit with his first homer since April 4 in the second. The Rays threatened again in the third, but stranded runners at first and second when Padilla struck out Carlos Pena after falling behind 3-0 in the count.

Sonnanstine settled after the shaky beginning to help the Rays get back into the game. The right-hander allowed two hits over his last three innings, and Tampa Bay trimmed Padilla's lead to 7-4 in the fourth on Hinske's 10th homer.

''I thought we had a pretty good chance when it was 7-5,'' Rays manager Joe Maddon said. ''The fight was there ... the intensity was there. In the end, they got us.''

Notes: Texas SS Michael Young has a 13-game hitting streak. ... Hamilton had gone a season-high four games without a RBI before driving in Young with his first-inning double. ... A moment of silence was observed before the game for former Rays pitcher Geremi Gonzalez , who was struck by lightning Sunday near his home in Venezuela. He was 6-16 with a 4.66 ERA for Tampa Bay in 2003 and 2004. ... Rangers INF Hank Blalock had a cortisone shot for carpal tunnel syndrome in his right wrist. He originally went on the 15-day disabled list with a left hamstring injury on April 29. He experienced soreness in the wrist last week.