Cardiff Blues need their best to beat Ospreys - Sam Warburton

Wales captain Sam Warburton says Cardiff Blues will need to be at their best to beat Welsh rivals Ospreys in the Pro12 at the Millennium Stadium on Saturday, 25 April.

Flanker Warburton, 26, was skipper as 10th-placed Blues were thrashed 36-17 away in Glasgow on Friday.

Title challengers Ospreys won 33-13 away at Italian side Treviso.

"It's going to take a huge performance to get a result - one of our best of the season," said Warburton.

"They're a top-quality side and we were well beaten at the Liberty Stadium [in October]."

More than 35,000 tickets have been sold so far for the 'Judgement Day' double-header at the home of Welsh rugby.

Newport Gwent Dragons take on Scarlets following the clash between Blues and Ospreys.

The Swansea-based region are fourth in the Pro12 table, four points behind leaders Glasgow, but 31 ahead of Blues.

Cardiff conceded a bonus point to the Warriors before the break on Friday and Warburton admitted the first 40 minutes against the Scottish side was a low point.

"That first half was probably one of the worst I've been involved with in a Blues shirt," he said.

Cardiff Blues captain Sam Warburton has won 54 Wales caps

But the Wales flanker says he is determined Blues finish the season strongly.

"I never find it hard to get motivated to play for Cardiff," he said.

"The games are spread out so we can go all guns blazing for the rest of the season, to try to put some pride back in the Blues jersey."

Caretaker coach Paul John backed up the importance of the Ospreys encounter.

"There's no bigger game than against the top region in Wales," said the former Pontypridd scrum-half, who added that he still had faith in the potential at his disposal.

"There's a lot of personal battles, a lot of people playing for [Wales] World Cup places," he added.