Mansfield's Boulding brothers both netted to see off the challenge of Blue Square South side Lewes.
The patient Stags broke through on 33 minutes when Michael Boulding turned in brother Rory's hard, low cross.
Rory grabbed his first senior goal seven minutes later with a powerful low finish from a tight angle.
The visitors' hopes faded further when Ian Simpemba was dismissed on 73 minutes for a second bookable offence and Ian Holmes headed home a third.
Mansfield: Muggleton, Bell (Kitchen 84), Mullins, Buxton, Martin, Hamshaw, D'Laryea, Dawson, Jelleyman, Rory Boulding (Holmes 78), Michael Boulding (McAliskey 85).
Subs Not Used: White, Sleath.
Goals: Michael Boulding 33, Rory Boulding 40, Holmes 82.
Lewes: Williams, Conroy, Robinson, Simpemba, Barness (Legge 64), Cade, Kennett (Drury 53), Wormull, Holloway, Binns (Griffiths 78), Booth.
Subs Not Used: Watts, Groves.
Sent Off: Simpemba (72).
Booked: Simpemba, Binns.
Ref: Carl Boyeson (E Yorkshire).