The Dolphins fell 15 points behind before Rishard Matthews finally got his side on the scoreboard with a touchdown late in the second quarter.
The AFC East outfit then produced a stirring comeback in the third quarter to take the lead, but a Bobby Rainey score early in the fourth gave the Buccaneers just enough to claim their first win of the season.
"We moved the ball well through the air, but we didn't have any balance. That caught up to us at the end of the game," Philbin told The AP.
"There's a lot of football left to be played. November and December is going to determine who moves forward. We have to learn from the mistakes we made and prepare better and play better."
The defeat leaves the Dolphins third in the AFC East, one win behind the New York Jets in second.