In a nine-try thriller that would have drama throughout, a double from Nicky Smith, scores from captain Justin Tipuric, Luke Morgan and a penalty try saw Toby Booth’s side home.
Cardiff were very much in the match with the scores locked at 12-12 at the break with Theo Cabango and Mason Grady both executing fine efforts.
The impressive Ben Thomas would have a hat-trick of assists as wing Gustavo Hamer-Webb would make the finish nail-biting.
It would be ill-discipline from the hosts that would be the final nail in the coffin for Cardiff with replacement Seb Davies dismissed late on. Even then Grady would collect his second to secure an attacking point for the Blues but it would be the Ospreys who would live to fight another day in the URC.
After the day’s early games results went their way, permutations would be out the window and in terms of play-off qualification the Ospreys would know a top-eight finish would be in their own hands. Simply nothing less than a try bonus point win would be enough over their fierce rivals.
In a frantic start, the Ospreys would force Cardiff into early errors leading to a series of scrum penalties in their opponent’s twenty-two.
Pressure would build and the departing Smith would power over from close range to open the scoring.
The lead, however, would be short-lived with Matt Sherratt’s side powering back to level the scoreline. Cabango’s individual brilliance seeing the wing squeeze into the corner after jinking through multiple Ospreys challenges after fine work from Thomas and Tinus De Beer.
The game though would turn into a physical and tense contest for a period before it would swing back the Ospreys way with a try of slick passing and excellent execution.

Veteran flanker Tipuric, leading from the front, starting the move before showing good hands to score in the corner after wing Keelan Giles had shown skill to take out multiple opponents before fly-half Dan Edwards would produce an exquisite reverse pass to his captain to finish the move.
Cardiff would show patience through several phases and would strike back on the stroke of half-time to level the scores as the pendulum would swing once more. Hooker Evan Lloyd showing great strength to find Thomas who would gain his second assist, feeding wing Grady superbly in the corner.
The Blues would start the second period the stronger but the Ospreys would soak up the pressure before having a spell of their own. Physicality telling on the Cardiff defense with multiple penalties awarded before Smith would eventually power over from close range for his second of the game.
The play would also see the Blues temporally a man down with forward Ben Donnell sent to the sin bin for a professional foul in the build-up to the try.
The Blues would manage the period well reducing the Ospreys lead to four points but even though they would back to a full quota, it would be Booth’s side who would score the all-important fourth try.
Morgan executing Edwards’ long pass out wide after an Ospreys scrum to score in the corner with Edwards slotting over the extras.
Cardiff would battle and would look to spoil the party for their rivals. The scores once again reduced with Thomas the instigator once more. The centre feeding wing Hamer-Webb to score wide, whilst also showing composure to slot over the conversion.
Discipline would be key in the last ten minutes as the next score would feel crucial. It would be Cardiff who would lose their own with an innocuous challenge from replacement Davies on Owen Watkin seeing the lock given a straight red.
From the resulting penalty, Owen Williams would kick to touch before a penalty try would be awarded after the Ospreys driving maul would be denied illegally.
A messy end to play would see lock Rory Thornton sent to the sin bin before Grady would score his second in added time with Cardiff finishing with 13 men.
It would be the Ospreys though who would secure a play-off spot for the first time since 2017 and will roll on to the last eight to Limerick to play Munster next weekend.
Ospreys prop Nicky Smith speaking after the game said:
“My head is scrambled, there were a bit of nerves around the hotel when we found out we could do it, it’s just credit to the boys, they’ve delivered today.
“We knew how difficult the task was going to be today, Cardiff were fantastic.
“I’m so proud of the boys, we deserve this.”
Ospreys XV:
Max Nagy; Luke Morgan, Owen Watkin, Keiran Williams, Keelan Giles; Dan Edwards Reuben Morgan-Williams; Nicky Smith, Dewi Lake, Tom Botha, James Ratti, Huw Sutton, Jac Morgan, Justin Tipuric (captain), Morgan Morris.
Replacements:
Sam Parry, Gareth Thomas, Rhys Henry, Victor Sekekete, Harri Deaves, Luke Davies, Owen Williams, Harri Houston.
Cardiff XV:
Cameron Winnett; Theo Cabango, Rey Lee-Lo, Ben Thomas (capt), Mason Grady; Tinus de Beer, Ellis Bevan; Rhys Carre, Evan Lloyd, Keiron Assiratti, Shane Lewis-Hughes, Rory Thornton, Ben Donnell, James Botham, Alun Lawrence.
Replacements:
Efan Daniel, Corey Domachowski, Rhys Litterick, Seb Davies, Lopeti Timani, Willis Halaholo, Jacob Beetham, Gabriel Hamer-Webb.
[Lead image: Ospreys Rugby]