Middlebrooks' blast in the eighth inning was his fifth in seven games. The Red Sox's top prospect has six homers -- good for third in the International League -- and a league-leading 20 RBIs in 15 games this season, his second at Pawtucket.
With 18 RBIs in his last eight games, Middlebrooks again led the charge as the PawSox clubbed five homers, including the first Triple-A blast of Alex Hassan's career, a grand slam. The 2011 Eastern League All-Star also walked and scored three times.
Middlebrooks is batting .370 with nine multi-hit games and four three-run homers. In his last seven starts, he's smacked five longballs, driven in 15 runs -- including four three-RBI efforts -- with five multi-hit games.
The third baseman, ranked No. 55 among MLB.com's Top 100 Prospects, was Boston's fifth-round pick in the 2007 Draft and earned MiLB.com, Eastern League and Futures Game All-Star honors last season after hitting .285 with 23 homers and 94 RBIs across three levels.
Mauro Gomez contributed a two-run homer and a solo shot, while Tony Thomas also went deep for Pawtucket, which has won five straight and eight of its last nine games.
Brandon Guyer, the Rays' No. 13 prospect, collected five hits and fell a double shy of the cycle for the Bulls, who have dropped five in a row.