Jevani Brown scored in each half as Exeter ran out 2-0 winners at struggling MK Dons.
Brown broke the deadlock from the spot nine minutes before the break, sending Jamie Cumming the wrong way after former Dons frontman Sam Nombe was brought down by Zak Jules.
The striker doubled his tally midway through the second half as he latched on to Archie Collins' deflected pass to fire home his 12th Sky Bet League One goal of the season.
The hosts had enjoyed the better of the opening stages and should have gone in front when Mo Eisa was played clean through but slotted wide with the goal at his mercy.
Daniel Harvie and Bradley Johnson were off target with efforts from distance while the latter saw a header drop inches wide in first-half stoppage time.
Eisa spurned two further presentable chances in the second period as a profligate Dons side failed to test Jokull Andresson, who marked the first appearance of his third Exeter loan spell with a clean sheet.