Cardiff Blues director of rugby Phil Davies has called on his players to prove their defensive mettle when they take on in-form Glasgow Warriors in the RaboDirect PRO12 on Saturday. After defeats in their opening two encounters the Warriors, under new head coach Gregor Townsend, come to Cardiff Arms Park on the back of three successive victories in the league. The Blues meanwhile suffered their biggest-ever home defeat since the region was formed in 2003 when Ulster were the visitors to Cardiff Arms Park last Friday. Cardiff have already been defeated at home by a Scottish side this campaign, losing 19-21 to Edinburgh in round two, and with the Warriors maintaining a strong record against Welsh opposition Davies knows his side have their work cut out for them. “This week it is about tightening up the defence, ensuring we make our one on one tackles effectively and continue to build our set piece,” he said. “We also need to get our scrum more consistent. Overall it is important to ensure the consistency is there and that we are more clinical. “It is important to encourage the players to play positive rugby; like when you see Tom James or Alex Cuthbert breaking from the back and getting the crowd on their feet. “As a coach you have to be objective and keep the players feeling as if they are moving forward. “Glasgow are a high quality team. They were unlucky at the start of the season but have won their last three games. “They are strong up front, and are lead by Alastair Kellock who is a quality international second row; the battle between him and Lou Reed is going to be interesting.” Davies brings back in Welsh international Leigh Halfpenny for the clash as Ceri Sweeney also returns at fly-half in place of Jason Tovey. The Warriors meanwhile show nine changes from the side that ran out comfortable winners over Zebre last time out. In the backs Peter Murchie comes in at full-back for his 50th appearance in a Warriors jersey, Alex Dunbar and Peter Horne resume their centre pairing, Sean Lamont replaces hamstring injury victim DTH van der Merwe on the left wing and Henry Pyrgos starts at scrum-half. Up front, Dougie Hall slots in at hooker, captain Kellock comes into the second row, John Barclay starts at openside and Ryan Wilson dons the No.8 jersey. Townsend said: “It's a sign of the strength in depth we have at the club this year that despite having ten key players injured, I firmly believe we're sending out a very strong side this week. “We've established momentum with wins in our last three games, and the challenge is now to sustain that at a very difficult away venue like the Arms Park. “We've only won there once before, back in 2002, and that record underlines just how passionate and difficult an environment Cardiff and their supporters create for opposition teams. We know how dangerous the Wales and Lions players in the Blues backline are, and they also have a very tough forward pack. “That said, we've demonstrated on a number of occasions in the recent past that we have both the ability and the mindset to win in tough arenas. We'll need to be as tenacious and clinical as we were against Ospreys.” At Arms Park, 6.30pm. Referee: Giuseppe Vivarini (FIR, 3rd competition game) Assistant Referees: Tim Hayes, Phil Fear (both WRU) Citing Commissioner: Denis Jones (WRU) TMO: Tony Rowlands (WRU) Live on S4C and BBC ALBA