Simon Easterby insists Scarlets need to be at their best to overcome the threat of Munster in the RaboDirect PRO12 on Saturday. Munster may have made eight changes to their side that beat Ospreys last time out but Scarlets head coach Easterby isn’t taking anything for granted. The Scarlets have won their last two matches in the RaboDirect PRO12, in Treviso and at home to Edinburgh, but have not won three in a row in the tournament since last April. The Welshmen have won three of their last four fixtures with Irish provinces at Parc y Scarlets and Easterby has made only once change to the side that secured victory over Edinburgh. Co-captain and British & Irish Lions centre Jonathan Davies returns and Easterby is keen to see his side step up to the plate. Easterby said: "Munster are a pretty good outfit at the minute and are pretty settled. They are still able to pick a very strong team despite missing a number of internationals. "We are under no illusion that they'll be coming here nothing less than well equipped to mix up their game and we will have to be at our best and far better defensively. "Having narrowly missed out on a victory late on in injury time against Munster at Musgrave Park before Christmas we've had plenty of motivation in training this week! “We put ourselves in a really good position to win away from home but gave them a foothold in the dying minutes and managed to stick at it." Munster's single defeat in the RaboDirect PRO12 since round three was 19-29 against Ulster at Ravenhill on January 3. The Munstermen are going for a clean sweep of eight successive wins over Welsh regions this season, a feat that has never been accomplished by any side before. The Scarlets 18-10 victory over Munster at Parc y Scarlets in February 2013 ended an impressive run of success for Munster in matches played in Llanelli – the home side never having won on their own park since March 2007. Donncha O'Callaghan joins Donnacha Ryan in the second-row with James Coughlan captaining the team. There are four changes in the backs with Duncan Williams taking the place of Cathal Sheridan at scrum-half with Ian Keatley remaining at out-half. Johne Murphy and Gerhard van den Heever are both drafted into the side on the wings with Simon Zebo moving to full-back. Elsewhere Denis Hurley comes in at centre while two of the four changes in the forwards involve the front-row with Irish international props Dave Kilcoyne and Stephen Archer joining hooker Duncan Casey who maintains his place. At Parc y Scarlets, 6.30pm. Live on S4C/RTE Referee: Dudley Phillips (IRFU, 41st competition game) Assistant Referees: Wayne Davies, Rhys Thomas (both WRU) Citing Commissioner: Gwyn Bowden (WRU) TMO: Tim Hayes (WRU)