Blair Henderson’s hat-trick helped Spartans breeze into the cinch League 1 play-off final after a 5-1 victory at Peterhead wrapped up a 7-2 aggregate success.Henderson’s late penalty gave Spartans, in their first season at senior level, the edge after the first leg in midweek and Cameron Russell put them ahead on Saturday after just three minutes, tucking home after some confusion in the Peterhead box following a cross.Henderson then headed home on the half hour before Marc McNulty teed up Bradley Whyte to lash home after 62 minutes.Danny Strachan pulled one back in the 66th minute but Peterhead’s flickering hopes were extinguished moments later when Jason Brown handled on the line and Henderson tucked away the resultant penalty.Henderson added gloss to the scoreline and completed his treble in the 78th minute as Spartans set up a two-leg showdown against Dumbarton next week.