The Blues were leading through Tyrese Shade’s sixth-minute goal, his first for the club since joining from League One Burton,
However, their Austrian keeper gifted the visitors an equaliser on 59 minutes when Ben Johnson’s cross from the right went straight through his hands and Jack McGlynn capitalised.
Then, 13 minutes from time, Schmid push out Ethan Galbraith’s shot and Ben Wilmot headed into an empty net to send the visitors to the top of the Championship.
And here are our Pompey ratings...
5. Madiodio Dia - 7
Was celebrating off-sides like winning goals, such is his love of defending. Brilliant covering tackle to deny McGlynn in the second half and another strong showing. | Jason Brown
6. Jayden Meghoma - 7
(Replaced by Zak Swanson on 75 mins) Did well up against the threat of Tchamadeu and also a regular threat down the left in attacking positions. | Jason Brown
7. Marlon Pack - 6
(Replaced by Rocco Shein on 75 mins) Back in the side with Mohamed missing through injury and fired one first-half effort just over the bar from outside the box which drew a round of applause. Not at his usual level and looked a little jaded. | Jason Brown
8. Ebou Adams - 7
First-half booking means Adams now suspended for one game, but ploughed on as ever, covering plenty of ground. Never lets the opposition settle and helped out Devlin defensively when Bombino was introduced. | Jason Brown