Pompey won at League Two side Stevenage in their latest pre-season encounter.
Ronan Curtis scored the only goal midway through the second half, arriving at the far post to head home Jamal Lowe's cross.
There were not an abundance of clear-cut chances at Broadhall Way, but the best ones all fell to the visitors.
Anton Walkes came closest to adding another goal for the Blues, with a neat chip that hit the crossbar.