The visitors were always up against it without two of their most experienced players - the injured Jamie Brown and the unavailable Luke King. That left boss Mick Catlin only naming one substitute in Connor May.
Gosport came under pressure from the start with the Magpies launching a series of attacks. Borough had a huge let off when Jordan Storey sent a header against the woodwork and the ball was scrambled away.
But it was one-way traffic and it was no surprise when the hosts made a 19th-minute breakthrough. David Jerrard split the Gosport defence with a good through ball and Arron Rodriguez lifted the ball over the advancing goalkeeper.
The shell-shocked visitors fell further behind two minutes later with the unmarked Ross Carmichael heading in at the far post from a corner.
Two further goals for the home side in as many minutes before the break ended the game as a contest. Rodriguez fired in his second of the night and Jerrad was easily put in before curling his shot past Lewis Watch in the Borough goal.
That made it 4-0 to Dorchester at the break and left the visitors fearing the worst.
There was little let up for Borough as they found themselves on the rack again at the start of the second period. Borough were working hard trying to stem the flow as the Magpies kept pushing forward.
Rodriguez completed his hat-trick with an excellent solo effort in the 66th minute to send Borough deeper into despair. The visitors only substitute May immediately replaced Matt Buse.
A predictable sixth goal soon followed with Dom Panasar-Dower getting in on the scoring act but Gosport refused to give up and were rewarded with late goals from Iffy Onwuachu and Max Smith.
The hosts, however, had the final say when captain, Gary Bowles, completed Boro’s misery with a seventh goal in the final minute.
Gosport Borough: Watch, Paige, Medway, Liss, Saidy, Saunders, Smith, Buse, Onwuachu, Woodward, Watts. Sub: May
Report: Kevin Ricketts (The News)
Updated 08:05 - 10 Oct 2017 by Site Manager