Last week the Blues surprised the Ospreys with a 43-6 win and will now want to knock the high flying Ulstermen from the top of the tree.
But it will require a supreme effort – Ulster not only top the table, but top the form guide as well having won five games in a row.
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In an attempt to shake up his stunned Ospreys side, coach Lyn Jones has dropped star man Gavin Henson after his nightmare performance against the Blues, with Adrian Durston coming in as his replacement for the match against Connacht.
The Warriors make the trip to Munster tonight hoping to reverse a losing trend that has seen them slide form top spot to fourth place – despite a 19-12 win over the Dragons last week. Munster are on an upward curve, moving out of the bottom three for the first time all season when they defeated Glasgow 26-10 last weekend.
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On Saturday, the Scarlets will look for maximum points against the Borders. The match is being played at the Racecourse Ground in Wrexham, but the unfamiliar surroundings should not pose too many problems for the second placed Scarlets. Their opponents sit rock bottom of the division, and will probably still be there at 5pm Saturday.
Rodney Parade will see an influx of Scottish fans when Edinburgh come to town on Saturday for the evening game. The Dragons have kept faith with the side that lost to the Warriors, despite heavy criticism from the media.
Edinburgh will be desperate for a win having gone from top to fifth spot following two heavy defeats in a row, firstly to the Ospreys 42-18, and last week losing to Ulster 41-3.