Exeter Chiefs kept alive their slim hopes of progressing in the LV= Cup with victory over the Ospreys at Sandy Park.
Ospreys were leading 10-8 at the interval through tries from Dafydd Howells and Morgan Allen
There were four tries in a nine-minute spell at the start of the second half with a second for Luke Cowan-Dickie and one from James Scaysbrook.
But the Ospreys came back to secure a bonus point with a touchdown from Matthew Jenkins, converted by Matthew Morgan, and Tom Grabham to level the scores.
James Phillips' try, converted by Ceri Sweeney, restored the Chiefs' lead before Don Armand added a fifth try to seal victory.
Exeter Chiefs: Tom James, Fetu'u Vainikolo, Sireli Naqelevuki, Tom Hendrickson, Ian Whitten, Ceri Sweeney (capt), Stuart Townsend; Carl Rimmer, Luke Cowan-Dickie, Lloyd Fairbrother, Will Carrick-Smith, Romana Graham, Don Armand, James Scaysbrook, James Phillips
Replacements: Greg Batemen, Kieran Davies, Craig Mitchell, Joel Conlon, Sam Simmonds, Jack Oulton, Gareth Steenson, Max Bodilly
Ospreys: Ross Jones; Tom Grabham, Jonathan Spratt (capt), Matthew Jenkins, Dafydd Howells; Matthew Morgan, Tom Habberfield; Marc Thomas, Matthew Dwyer, Dan Suter, Lloyd Peers, Rhodri Hughes, Tyler Ardron, Morgan Allen, Arthur Ellis.
Replacements: Rhys Hutchinson, Nicky Smith, Joe Rees, Adam Beard, Dan Baker, Lloyd Evans, Luke Price, Aisea Natoga.
Referee: Ben Whitehouse (RFU).