Frikkie Welsh and Andy Williams scored the tries and Olly Barkley kicked 14 points as Bath held on for their win.
The Ospreys are the only Welsh region without a victory in the new Anglo-Welsh Powergen Cup. They were undone by a side far better equipped to make the most of the chances that came along.
The Ospreys dominated long periods of the game and twice led their opponents. But without Gavin Henson, Shane Williams, Stefan Terblanche and Sonny Parker in their ranks they had precious little to show for their efforts.
Henson still dominated the terrace talk at the New Stadium, following his scathing criticism of Clive Woodward's methods and tactics with the British Lions in New Zealand.
His understudy, Matthew Jones, created the game's opening try with a moment a pure opportunism inside eight minutes. Handed a penalty five yards from Bath's line, Jones spotted Richard Mustoe hovering out wide and delivered a pin-point cross-field kick. Bath's Tom Cheeseman clattered into Mustoe in mid-air and the referee Nigel Owens awarded a penalty try.
It was a rare lapse in concentration for Bath's defence, though in attack they made their rare visits into Ospreys territory count. Danny Grewcock was impressive, for once legally stamping his authority on the game. He also showed a nifty pair of hands to send Welsh over to score.
It was not until the second half that the Ospreys rediscovered their finishing touch, and again it was Jones who provided the cutting edge. The lock Ian Evans galloped down the right and Damien Karauna went close before Jones darted through.
Yet Bath were calmness personified and showed a ruthlessness to make sure they came away with points in some shape or form on each attack. The pick of the bunch was a try by the scrum-half Andy Williams against his former club.
Shaun Connor missed a late penalty that would have brought the Ospreys to within a point. His miss summed up his team's night.
Ospreys: Tries Penalty, M Jones; Conversions M Jones 2; Penalties M Jones, Connor. Bath: Tries Welsh, Williams; Conversion Barkley. Penalties Barkley 4. Drop goal Malone.
Ospreys: D Karauna; R Mustoe, A Bishop, L Davies, A Brew; M Jones (S Connor, 67), J Spice (M Roberts, 75); P James (D Jones, 67), B Williams (capt, R Hibbard, 80), A Jones (D Jones, 53-67), A Newman (B Cockbain, 67), I Evans, J Thomas (L Beach, 80), R Pugh, R Jones (A Lloyd, 40).
Bath: M Perry (capt); S Finau, T Cheeseman, R Davies (C Malone, 47), B Welsh (N Walshe, 30); O Barkley, A Williams; D Barnes, P Dixon (R Hawkins, 78), D Bell (M Stevens, 53), J Hudson, D Grewcock (S Borthwick, 65), C Goodman, J Scaysbrook, G Delve.
Referee: N Owens (Wales).Reuse content