Connacht battled back bravely after conceding three first-half tries and looked good for a bonus point but in the end were blown away by the sheer power of the Ospreys.
Three defeats in the opening four games leaves Connacht stuck near the bottom of the table and they will get nothing easy in Treviso next weekend when they head to Italy looking for a boost before their Heineken Cup opener against Saracens. Connacht started well and Craig Ronaldson got them off the mark, but then he had a pass intercepted and Dan Biggar raced through to score.
Biggar punished Connacht every time and his half-back partner Tito Tebaldi was also superb as Ospreys raced in three tries in each half. Richard Fussell and Eli Walker crossed for Ospreys but three more penalties from Ronaldson kept Connacht in touch and they had a fighting chance at the break when they trailed 22-12.
Dan Parks, on for the injured Ronaldson, used his experience to give Connacht a launching pad and they got a big break after 55 minutes following a break by Ali Muldowney down the left. He was nabbed but Danie Poolman was on his shoulder and he took the ball at speed and raced through to score. Parks added the points to leave Connacht trailing by just 22-19.
But Connacht's hopes of the home support suffered a blow four minutes later when Ospreys wrapped up the try bonus point when scrum-half Tebaldi sped through to score under the posts. Biggar's conversion made it 29-19.
Kieran Marmion responded with a try for Connacht with Parks converting to leave three between them with 18 minutes left. But any hopes of a bonus point were dashed as Ospreys finished strongly with late scores from Jeff Hassler and Alan Wyn Jones.
Scorers – Connacht: D Poolman, K Marmion try each; D Parks 2 cons; C Ronaldson 4 pens. Ospreys: D Biggar, R Fussell, E Walker, T Tebaldi, J Hassler, AW Jones tries; D Biggar 5 cons; D Biggar pen
Connacht: G Duffy; D Poolman, R Henshaw, E Griffin, M Healy (F Carr 43); C Ronaldson (D Parks 38), K Marmion (P O'Donohoe 73); B Wilkinson (R Ah You 65), S Henry (J Rael 74), N White (R Loughney 73); M Swift (A Muldowney 49), C Clarke (G Naoupu 73); A Browne, J Heenan, J Muldoon.
Ospreys: R Fussell (M Morgan 79); J Hassler, B John, J Spratt (A Bishop 58), E Walker; D Biggar, T Tebaldi (T Habberfield 77); D Jones (R Bevington 56), S Baldwin (R Hibbard 52), A Jones (A Jarvis 73); AW Jones, I Evans (T Ardron 64); J King, J Tipuric, M Allen (J Bearman 50).
Referee: A McMenemy (SRU).