St Mirren's final pre-season match ended in defeat as two late goals gave Morton victory.
The Buddies dominated the opening hour or so but couldn't find the net. And two goals in two minutes late in the half saw the hosts win.
Saints first real chance came on 12 minutes with Alex Gogic rose the highest to meet Ryan Strain's corner only for the header to be brilliantly saved by Morton stopper Ryan Mullen.
Ethan Sutherland forced the Morton goalkeeper into another good stop with his half-volley from inside the area tipped over the bar on 30 minutes. Saints should have scored three minutes later but Toyosi Olusanya crashed his close-range header off the bar.
The home side's best chance of the half came three minutes before the interval when Robbie Muirhead's bullet free-kick from distance flew just over the bar from around 30 yards from goal.
Stephen Robinson made a triple change at the interval with new boy Conor McMenamin on for his first taste of Saints action as well as Richard Taylor and Caolan Boyd-Munce. They replaced Marcus Fraser, Ethan Sutherland and Alex Greive.
Morton were inches away from taking the lead a little over 10 minutes into the second-half when Robbie Crawford flicked an effort just by the post.
O'Hara came closest to finding our opener not long after the hour mark, but his strike was blocked by the face of the Morton goalkeeper.
The hosts would take the lead heading into the final 10 minutes of the match after they were awarded a spot-kick. A long ball over the top caught out the Saints defence and Zach Hemming clashed with a Morton forward which saw referee David Munro point to the spot. Muirhead stepped up and fired home. Morton added a quickfire second with McGrattan slotting home less than two minutes after the opener.
Full-Time: Morton 2-0 St Mirren
St Mirren: Hemming, Fraser (Boyd-Munce 46), Gallagher, Dunne, Strain (Flynn 67), Kiltie, Gogic, O'Hara (c), Sutherland (R.Taylor 46), Olusanya (Mandron 59), Greive (McMenamin 46)
Subs Not Used: Urminsky, Kenny, F.Taylor, Jamieson