Top Trinity side end FA Cup run.
Chasetown suffered their worst ever FA Cup defeat, but battled to the end netting two late consolation goals.
Trinity took an early lead with Ross Hannah giving the hosts the advantage after four minutes.
Ashley Worsfold made it 2-0 three minutes later with a header from a free kick.
Shane Clarke killed the tie off midway through the half with a well placed low shot past Curtis Pond.
Any chance of a dramatic comeback was killed early in the second half. A Chasetown attack broke down and Gainsborough swept upfield. Pond tried to get there but Worsfold fired into an empty net from 40 yards.
The Lincolnshire side added to their total after substitute Simon Russell beat the offside trap and confidently fired past Pond.
Gainsborough’s 6th was a worldy of a strike from Alex Byrne which was unstoppable by any goalkeeper, right in the top corner of the goal.
The Premier side exercised their class and got no more than they deserved with skipper Liam King firing in a seventh as Gainsborough aimed for their club record score. That goal came after a defensive mix up and an own goal gave Trinity their all time record score.
Chasetown never gave up attacking and pulled one back with an effort that deflected into the path of George Cater who volleyed home from 6 yards.
Jack Langston was then a whisker wide and then Chasetown further reduced the deficit with a low shot past Jon Stewart from Jake Lovatt.