The Stormers' chances of qualifying for a URC play-off match at home ended on Saturday as the Ospreys won 27-21 in Cape Town.
The inaugural URC champions put in a dominant performance and were down 17-7 to the Welsh region at half-time, with Toby Booth's charge dominating the match.
Luke Morgan (two), Sam Parry and Hari Deaves all scored for the visitors, with Jack Walsh adding two conversions and a penalty.
The Stormers scored incredible tries from Dan du Plessis and Evan Roos, with Manie Livbok scoring both goals, but it wasn't enough to see them win.
However, a penalty try on the final play of the match earned them a losing bonus point, which ensured that the Stormers retained their lead over the Welsh team.
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The Ospreys took the lead in the 9th minute, with Dan Edwards deftly kicking into space behind the Stormers defence, and Morgan finishing well to take the lead and shake things up.
Edwards' effort to convert went just wide, but the visitors' impressive opener was soon followed by a superb try for the Stormers, started and finished by du Plessis, with contributions from Wandisile Simelane and Nama Shaba. was overtaken by
Livbok scored, but the Ospreys continued to relish the challenge ahead and were back in front after 26 minutes when Parry fired over from close range under constant pressure. Toby Booth's side responded brilliantly and scored their third try just before half-time.
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Livbok's cross-field kick was latched onto by Walsh, who swung past the Stormers' defenders and sent in Morgan for his second try, before converting for a 17-7 interval lead.
The Stormers had to find a quick response and conjured up a score from deep within their own 22 just five minutes into the second half.
Full-back Warrick Geraint was the starting point, with Simelane and Livbok creating devastating effects in midfield, with Roos finishing in style and Livbok converting to make the game three points.
However, the Ospreys kicked into gear again just when it looked like their opponents might take the lead.
Another spell of possession deep in the Stormers half was rewarded with a try from Deaves, converted by Walsh, to give the Ospreys a 24-14 lead with 15 minutes remaining.
The Stormers inevitably gave their best to the opposition in the final moments, but were unable to find a breakthrough and an 80th minute penalty try was just a consolation for the lost bonus point, with the Ospreys losing to a scene of jubilation in the camp. I ended things inside.
Stormers v Ospreys
Stormers: 15 Warrick Guerin, 14 Suleiman Hartzenberg, 13 Wandisile Simelane, 12 Dan du Plessis, 11 Ben Roeder, 10 Manny Livbok, 9 Stefan Ungerer, 8 Evan Roos, 7 Hajiba Deimani, 6 Nama Shaba, 5 Gary Porter, 4 Adre Smith, 3 Frans Malherbe (c), 2 JJ Kotze, 1 Brok Harris
Replacement: 16 Skala Ntubeni, 17 Kwenzo Brose, 18 Saji Sandy, 19 Ruben van Heerden, 20 Willy Engelbrecht, 21 Marcel Theunissen, 22 Paul de Wet, 23 Damian Willemse
Osprey: 15 Max Nagy, 14 Luke Morgan, 13 Kieran Williams, 12 Owen Watkin, 11 Kieran Giles, 10 Dan Edwards, 9 Ruben Morgan-Williams, 8 Morgan Morris (c), 7 Hari Deaves, 6 James Ratty, 5 Hugh Sutton, 4 Victor Sekekete, 3 Reece Henry, 2 Sam Parry, 1 Nicky Smith
Replacement: 16 Lewis Lloyd, 17 Garyn Phillips, 18 Ben Warren, 19 Adam Beard, 20 Jandre Rudolph, 21 Luke Davies, 22 Jack Walsh, 23 Evaldy Boshoff
venue: DHL Stadium, Cape Town
kick off: Local time 19:15 (BST 18:15)
Referee: Andrew Brace (IRFU)
Assistant referee: Kwengile Yazweni (SARU), Hanl van Rooyen (SARU)
TMO: Chris Buzby (IRFU)
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