Scott Carson has hailed the blossoming partnership between Jonas Olsson and Shelton Martis at the heart of West Brom's defence.Saturday's 1-1 draw with Bolton leaves the Baggies seven points from safety with just eight matches left to play - but Carson is refusing to throw in the towel.Albion's main Achilles heel this season, along with a lack of a proven top-flight goalscorer, has been a brittle backline that has often undermined some enterprising football at The Hawthorns.It is, though, a situation that has improved of late since Olsson and Martis were paired together as a new-look central defensive partnership.Carson has certainly gained confidence from playing behind a solid looking backline."Jonas has made a difference, as has Shely," he told the club's official website. "They were very solid and I feel very confident playing behind them."When they kick it they kick it and when they head it they head it."I won't take anything away from Leon (Barnett) or Abou (Meite) but Shelton and Jonas have clicked and maybe will be a successful partnership"When you play behind the same back four every week then you generally know what to expect but we've had injuries and it's not been easy for the manager. There's nothing we can do about that."