Kal Naismith scored the only goal of the game as Portsmouth defeated Plymouth 1-0 at Fratton Park.The forward netted halfway through the first half after Pilgrims goalkeeper Remi Matthews failed to deal with a long ball.Pompey started the brighter and had the visitors on the back foot for most of the match.The home side only had to wait seven minutes for their first chance, Jamal Lowe turned on the ball but his shot was blocked.Plymouth's best chance came in the 30th minute after defender Yann Songo'o was left alone inside the box, but his header went over the bar.Pompey forward Conor Chaplin claimed for a penalty in the 77th minute after going down in the area but referee Robert Madley waived play on.Naismith almost doubled the score in the 78th minute but his shot rebounded off the far post.In injury time Plymouth forward Nadir Ciftci could have salvaged a point for the away side but failed to connect with the ball and the chance went begging.