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Devils recovered from Darian Dzuirzynski's early goal to lead 3-1 with goals by Andrew Lord, Patrick Asselin and Sean Bentivoglio.
Mark Heatley reduced the lead with four minutes to go before Joey Haddad sealed the points for Devils.
Cardiff play Sheffield Steelers in the Challenge Cup final on Sunday.
Cardiff Devils are nine points clear of Belfast at the top of Ice Hockey's Elite League following their 4-2 win over Manchester Storm on Friday night.