The Ospreys stayed on course for a Heineken Cup place by running in nine tries against Borders at the Gnoll.
Ospreys (27) 60
Tries: Henson 3, A Williams, S Williams 2, Terblanche, Thomas, Seveali'i.
Cons: Henson 6.
Borders (7) 7
The vital fourth try for a bonus point was in the bag within 26 minutes, the pick a jinking masterpiece for the first of Shane Williams' two scores.
Gavin Henson led the way with three tries in a 30-point haul, while Andy Williams, Stefan Terblanche, Jon Thomas and Elvis Seveali'i all scored.
Borders had just a Chris Cusiter try and stay bottom of the Celtic League.
The Ospreys were at Borders from the start, re-gathering the kick-off and driving hard into the visitors' 22.
The Scottish defence eventually lost its discipline, giving Henson an easy penalty kick for an early 3-0 Ospreys lead.
The Welsh side produced a fine backs move to send James Storey over after eight minutes, only to have the try disallowed after play was brought back for fighting.
Ospreys prop Andrew Millward was adjudged to have thrown the first punch, but he and opponent Craig Dunlea both got 10 minutes in the sin-bin.
It took just six minutes more for the Ospreys to claim the opening try, Terblanche reclaiming his up-and-under to set Andy Williams into open space.
The scrum-half drew the Borders defence right, before passing inside to Henson at full speed to go over.
The full-back couldn't convert his own try but made no mistake with the next two as the Ospreys added two more tries in double quick time.
First Andy Williams sniped over from the base of a ruck, then Shane Williams produced the score of the night as three side-steps and raw pace sent the Wales wing over the whitewash.
The Ospreys had targetted this match for maximum points in the race for Heineken Cup places and claimed a bonus point within 26 minutes with their fourth try of the match.
Shaun Connor let the ball do the work, as the Ospreys ran staright and passed smoothly to send Henson over in the left-hand corner for his second unconverted try of the night.
Maybe thinking the hard work was done, the home side took their foot off the accelerator and wing Craig Moir broke through to send current Scotland scrum-half Cusiter over, Gareth Morton converting to make it 27-7 at half-time.
Within seven minutes of the restart Henson had his hat-trick, as Shane Williams let Scottish tacklers swarm down on him before flipping a pass to his rampaging full-back, who also converted.
The Ospreys began to run Borders ragged and Shane Williams soon added his second with an outrageous swan-dive in the right corner, having received the scoring pass just a metre from the line.
Former Springbok wing Terblanche claimed the Ospreys' seventh try after hacking on a loose ball, while replacement Jon Thomas took the home side over the 50-point barrier - Henson converting both tries.
Seveali'i added the Ospreys' ninth try in injury time to round off a very satisfactory night for coach Lyn Jones.
The Ospreys are now eight points clear of the Blues, who play on Saturday away to the Dragons and sit lowest in the table of the five Welsh sides.
Ospreys: G Henson, S Terblanche, J Storey, D Tiueti, S Williams, S Connor, A Williams, D Jones, B Williams (capt), A Millward, A Newman, L Tait, J Bater, S Tandy, N Bonner-Evans.
Replacements: C Wells, P James, J Thomas, R Pugh, E Seveali'i, R Wells, G Morris.
Borders: G Morton, S Cranston, J Stuart, K Utterson (capt), C Moir, C MacRae, C Cusiter, C Dunlea, S Scott, B Douglas, D Weir, C Stewart, S MacLeod, M Lee, K Brown.
Replacements: R Ford, G Cross, A Davidson, J Dalziel, I Fairley, I Berthinussen, A Turnbull.
Referee: Ally McKay (Ireland).