Conor Chaplin got Pompey's first win of 2018 in dramatic last-ditch fashion at MK Dons.
Chaplin struck in the 94th minute to ensure Kenny Jackett's men came from behind to pick up a late, late 2-1 success
That ensured there were wild scenes of celebration among the 6,257 army of travelling fans at Stadium MK.
Matt Clarke celebrated his 100th Blues appearance by heading home with six minutes left.
Then came Chaplin's intervention with his first goal since November.
The home side had taken the lead through Ike Ugbo's 21st-minute opener, before the pendulum swung Pompey's way late on.
Kenny Jackett's men were indebted to Luke McGee who made a series of fine saves after being recalled following Stephen Henderson's injury.
Despite his pre-match indications, Jackett opted to use Anton Walkes at right-back and bring Oli Hawkins into defence in place of the suspended Christian Burgess.
The game flowed from end to end early on, but the home side should have been in front after 12 minutes when Kieran Agard was put clear by Ed Upson - yet he skewed his shot horribly wide.
That didn't matter when MK Dons went in front after 21 minutes as Agard's shot was saved by McGee, but Ugbo fired the loose ball in off the post.
McGee made two excellent saves to keep out Callum Brittain's 25-yarder and Scott Wootton's unopposed header from the resulting corner.
Before that Brett Pitman's impudent lob in the 31st minute represented Pompey's best effort, but was tipped over by the back-pedalling Lee Nicholls.
The Blues were again indebted to McGee who made two quick-fire saves after the restart to keep out Ugbo as he was clear on goal - and then tip over Upson's header.
Pitman nearly forced a solo effort home in the 62nd minute, but Wootton cleared the ball as is headed for the net.
Four minutes later it was sub Jamal Lowe in on goal, but he fired his scissor kick over as he was placed under pressure.
Oli Hawkins was the width of the post from levelling with 13 minutes left as his header came back off the woodwork.
But Clarke sparked away fan celebrations with six minutes left when he headed Donohue's cross past Nicholls.
Pompey were pushing for the winner at the death and it came in dramatic fashion with virtually the last kick from Chaplin - sparkling jubilant scenes among the Pompey fans.