Buckner pounced on the ball during a goal mouth melee on eight minutes to start the scoring in this action-packed Sussex Hockey Division Four fixture.
Minutes later Buckner buried a short corner shot past the keeper after Saxons continued to build the pressure on the visitors.
Midfield dynamo Rob Mercer skipped into the D in the 26th minute and took out half of Southwick's defence allowing Buckner to tap home from close range to complete his hat-trick.
In the second half, Saxons pushed on and were soon rewarded when 14-year-old Jonnie Orr dribbled into the D and smashed the ball past the on-coming keeper for his debut league goal.
Southwick then fought back and earned a penalty when a goal-bound shot struck Micky Acott's foot and was swiftly dispatched.
On the hour, winger Lloyd Williams latched onto Peter Klein's cross and fired in from close range scoring a debut league goal to make it 5-1.
Southwick scored a second goal from a short corner on 65 minutes.
Buckner said: "We worked hard from start to finish and deserved our win. And it was nice to see young Jonnie Orr getting on the score sheet for the first time in adult men's league hockey. He works hard at training, is really keen and enjoys his hockey. I also want to mention Lloyd Williams who worked very hard and was rewarded with his first goal for the team.
"The whole team put a shift in and the game was played in great spirit."
Saxons travel to Chichester V on Saturday (January 14) for a 12pm push back.
Man of the match: Les Cornish
Team: Heath, Cornish, Chapman, Whitehead, Cornelius, Acott, Patel, Mercer, Williams, Buckner (c) Orr, Woodford, Hooton, Klein