Pompey brought the curtain down on a memorable campaign with victory at Lincoln.
The 2-0 success ensured the League One champions ended with an impressive 97 points on the board.
Will Norris saved a Danny Mândroiu penalty early in the second half and John Mousinho's men made their opponents pay.
Late goals from Myles Peart-Harris and Paddy Lane got the job done, as a much-changed side ended the Imps' play-off hopes.