Danny Cowley’s side now find themselves fourth in the table after two draws and a defeat in their past three games – and nine points adrift of league leaders Plymouth.
The Blues do have two games in hand on both the Pilgrims and second-placed Ipswich.
Third-placed Sheffield Wednesday have also played an additional two games, so all is not lost for Pompey with just a quarter of the season gone.
But how do the data experts at fivethirtyeight.com believe Cowley’s side and others will fare between now and next May?
We’ve taken a look at their latest analytics to see who they think will remain in the title and promotion hunt and who might fall away.
Here’s what we found...