Aaron Wilbraham grabbed an equaliser for 10-man Milton Keynes Dons after Clive Platt had given Colchester a first-half lead against his old club.
Mark Yeates had fed Platt to put Colchester ahead from close range.
Milton Keynes were reduced to 10 men when winger Jason Puncheon was sent off for a two-footed lunge at Dean Hammond.
But Wilbraham headed in Jemal Johnson's corner to ensure honours finished even, although Steven Gillespie missed a late chance to win it for Colchester.
Milton Keynes Dons: Gueret, Cummings (Stirling 46), O'Hanlon, Llera, Lewington, Johnson, Howell, Leven (Wright 39), Puncheon, Wilbraham, Baldock (Flo 78).
Subs Not Used: Abbey, Gerba.
Sent Off: Puncheon (61).
Booked: Wilbraham, Johnson, Howell.
Goals: Wilbraham 65.
Colchester: Walker, Maybury, Reid, Baldwin, Jackson, Izzet, Hammond, Perkins, Yeates (Wordsworth 87), Platt (Gillespie 71), Vernon.
Subs Not Used: Cousins, White, Heath.
Booked: Izzet.
Goals: Platt 12.
Att: 8,408
Ref: Anthony Taylor (Greater Manchester).