Peterhead will play Forfar in the Ladbrokes League One play-off final after beating 10-man Montrose 3-0 on Saturday to wrap up a 4-1 aggregate victory.Rory McAllister headed the hosts in front in the 34th minute before doubling their lead from the spot six minutes into the second half after Nicky Riley was brought down in the box.Montrose were reduced to 10 men when Matty Smith was shown a straight red in the 69th minute.And things went from bad to worse for the visitors when Jordon Brown made it 3-0 in stoppage time.