Ulster’s Robbie Diack has challenged his teammates to prove they are a top-class outfit by making a seamless transition back to RaboDirect PRO12 action. Ulster host Cardiff Blues on Friday with both sides on a high following impressive Heineken Cup displays with the Irish side beating Leicester Tigers and Montpellier, while the Blues recovered from losing against Exeter Chiefs to stun holders Toulon. Diack and co have now won five straight matches in all competitions having lost their opening two league matches of the season and will expect to keep that run going when the Blues arrive in Belfast. And while South African No.8 Diack believes Ulster are in top form, he urged the players to prove they can handle the rigours of challenging on multiple fronts by keeping their run going. "Great teams need to produce back-to-back performances, no matter what the competition is or whatever opposition you are playing," Diack said. "Cardiff had a fantastic win last week, so I think, like us, they're going to have a lot of momentum and a huge amount of self-belief, too. "We've just to keep on building on this momentum we have created. We have two more weeks of hard work before we get a bit of a break for the (autumn) internationals, so we want to make these games count." "There is a huge amount of self-belief in this team at the moment so we're excited about this game. “Hopefully we will play well again this Friday night and keep things going forward." Jared Payne moves from fullback to outside centre, with Darren Cave selected on the bench. Stuart Olding starts his first game for Ulster at 15. Up front, Callum Black starts at loosehead with Tom Court, who was named in Joe Schmidt's Ireland squad this week, moving to the bench. Cardiff Blues’ season to date has been mixed with the 19-15 win over Toulon the obvious high in a season which also includes a shock home reverse at the hands of Zebre – the Italian side’s first RaboDirect PRO12 victory. Friday’s trip to a packed Ravenhill will prove another major test for the Blues and Richard Smith makes his first start of the season, having been named on the wing to replace the injured Alex Cuthbert. The other changes to the starting line-up sees Dafydd Hewitt comes in at centre for Owen Williams, with Cory Allen moving to outside centre. And director of rugby Phil Davies has urged his players to kick on from their win over the French giants and prove it was not simply a one off. "It was obviously a good performance against Toulon," he said. "It has enthused everyone, the singing at the end with all the supporters and the players really enjoyed the occasion. "Hopefully it is another milestone and a step forward for us. We have had a couple of disappointing experiences in the last couple of weeks, but to beat the European champions at home was a positive in this squad's progression. "But now it is vital we back it up. The belief that Saturday has given us will help us understand the level we need to hit every week. "We won the game against Toulon without a few of our most experienced players and the boys that stepped in did a great job. Now we need to keep that going in the RaboDirect PRO12." At Ravenhill Stadium, 7.05pm. Live on BBC NI Referee: Giuseppe Vivarini (FIR, 9th competition game) Assistant Referees: Gary Conway, Eanna O’Dowd (both IRFU) Citing Commissioner: Eddie Walsh (IRFU) TMO: Peter Ferguson (IRFU)