THE Shrimps let a three goal lead slip with a late goal denying them three points at Fratton Park.
Jayden Stockley's 94th minute diving header earned big spending Pompey a point.
Morecambe took the lead in the 10th minute with Tom Barkhuizen marking his debut with a goal.
The Shrimps played the ball out of defence and Barkhuizen brush past two weak Portsmouth challenges before drilling a low shot past Brian Murphy.
The home side hit back with Gary Roberts flashing a shot inches wide of the left hand post before the Shrimps stunned the home supporters for a second on 26 minutes. Jamie Devitt drilled in a right wing corner and Alan Goodall beat his man with a near post run to head home from six yards out.
Paul Cook's side continued to play some excellent football with Kyle Bennett forcing a fine save from Roche before the Shrimps went close to a third when Aaron Wildig hit the crossbar with a delicate chip from the edge of the area.
The Morecambe midfielder then missed a golden opportunity to add a third when played in by Shaun Miller's delicate lay off but missed the target from just six yards out.
Morecambe were not made to wait long for another goal however as they produced another fine break to extend their lead with Andy Fleming volleying home Devitt's cross at full stretch.
The Portsmouth comeback started on 42 minutes with a superb Roberts free kick from the edge of the area.
They took that confidence into the second half with Roberts scoring a second on 65 minutes when he was given too much space in the box to curl an effort past Roche from 18 yards.
The home side then had a man sent off when Enda Stephens saw red for a second bookable offence on 71 minutes.
Despite having a man less Portsmouth maintained the pressure and scored a late leveller when substitute Stockley threw himself to head home a right wing cross to cap a fine game.
Portsmouth: Murphy, Davies (rep Webster 74), Burgess, Clarke, Stevens, Bennett, Atangana, Doyle, Tubbs (rep Stockley 70), Evans (rep McGurk 79). Roberts. Subs not used: Jones, Chaplin, Hollands, Haunstrup.
Morecambe: Roche, Beeley, Parrish, Dugdale, Wilson, Wildig, Goodall (rep Kenyon 47), Devitt, Fleming, Barkhuizen (rep Molyneux 56), Miller (rep McGowan 68). Subs not used: Thompson, Mullin, Bailey, Ryan.
Ref: R East.