BBC Sport - Pro 12: Can the Cardiff Blues upset the Ospreys?
Blues aim to dent Ospreys' start
- From the section Wales
The Ospreys have not lost a Welsh derby in the Pro12 under head coach Steve Tandy.
They have a 100% record in the competition so far this season while the Cardiff Blues only have one win going to into Sunday's match.
Join Gareth Roberts, Deiniol Jones and Ken Owens on Clwb Rygbi today for live coverage on S4C from 1545 BST.
Full English commentary is available on the red button and on BBC Radio Wales.