Bench coach Rob Thomson managed his first big league game.
The Rays took advantage of Kennedy's wildness to score six times in the first three innings - five in the third - and then added seven runs in the eighth off relievers LaTroy Hawkins and Kyle Farnsworth.
In all, the Rays had 15 hits off six Yankees pitchers. Every position player had at least a hit and scored a run except Dioner Navarro, who was hit for by Riggans in the third. Navarro left with a cut on his throwing hand.
Kennedy (0-1), one of the trio of touted pitchers 23 years old and younger who are expected to anchor the Yankees rotation for years to come, relies on precise command, something he lacked in his fourth career start. He walked four and threw only 32 of 70 pitches for strikes.
Former Mets left fielder Cliff Floyd homered to right leading off the eighth against Hawkins and rounded the bases to a loud Bronx cheer. Hakwins gave up six runs in the inning. Pena, the first batter facing Farnsworth, hit a drive into the upper deck in right to complete the scoring in a seven-run eighth and make it 13-4.
Andy Pettitte follows Kennedy and makes his first start Saturday after a turbulent offseason, where he was named in the Mitchell report, admitted to using human growth hormone and gave a deposition and affidavit to a House committee contradicting friend Roger Clemens' testimony.
It was the first regular-season meeting between the Yankees and Rays since they fought and exchanged nasty words during spring training.
The Yankees played without centerfielder Melky Cabrera and the Rays were without Jonny Gomes. Each dropped their appeals of suspensions - which were reduced by a game each - for their roles in the bench-clearing scrap on March 12. Cabrera is out for two games and Gomes for one.
Yankees reserve Shelley Duncan also dropped his appeal and will sit out two games - reduced from three - starting Sunday. He instigated the fight by making a spikes-high hard slide into Rays second baseman Akinori Iwamura. Tampa Bay manager Joe Maddon called the play "borderline criminal."
Duncan's hard slide came four days after Rays infielder Elliot Johnson barreled into Yankees catcher Francisco Cervelli, breaking his hand. At the time, Girardi angrily complained the play was uncalled for in spring training.
The Yankees, who scored just eight runs in the first three games of the season, hit Andy Sonnanstine (1-0) hard in the bottom of the third and plated four runs on five hits. Hideki Matsui hit his first homer, Derek Jeter drove in a run with a triple off the wall in center, Bobby Abreu had a run-scoring groundout and Jason Giambi hit an RBI double.
Otherwise, Sonnannstine shut the Yankees down for six innings. He gave up one other hit and struck out four in a start pushed back a day because of a rainout in Baltimore.
