Ronan Curtis scored his first goal of the season and the Blues’ first in 434 minutes of League One football.
Yet it wasn’t enough to claim victory after goals either side of half-time from Joe Ironside and Liam O’Neil handed the U’s all three points.
Here’s how our chief sports writer rated the Pompey players’ performance…
1. Gavin Bazunu - 6
Almost kept out the second goal but otherwise asked to distribute from the back.
2. Mahlon Romeo - 7
Positive and direct, particularly in the second half, to emerge with credit.
3. Paul Downing - 7
(Replaced by George Hirst on 66 minutes): Composed on his comeback and made way for a tactical change.
4. Sean Raggett - 6
Continues to look impressive this season but headed clearance led to second goal.