Pompey Academy made an early exit from the Youth Alliance Cup after losing 3-1 on penalties following a 1-1 draw at Oxford.
They took the lead in the first half when Dan Cadman (pictured) raced between two defenders to convert a cross from the right.
But the hosts made the most of changing conditions after the interval and Gatlin O’Donkor fired them back on level terms.
Harvey Rew netted for the Blues in the shoot-out, but Charlie Bell, Harry Jewitt-White and Izzy Kaba could not convert their attempts and Oxford were more clinical.
Professional development phase coach Liam Daish said: “We played very well and it was a return to the performance levels shown in our recent league win over Exeter.
“We made good decisions, passed the ball around with confidence, dominated possession and opened our opponents up on a few occasions.
“Dan did well to attack the space from a very good cross and it meant we were deservedly ahead at the break.
"There were a lot of positives and it was a good all-round display – we looked in control before the elements made everything a bit frantic."
“But then the heavens opened at the start of the second half. The wind and rain were against us and it was almost unplayable at times.
“We struggled to deal with that and the momentum started to switch to Oxford, although we stuck in there.
“Then there was a bit of controversy, as we thought we should have had a corner, but the decision went the other way and they broke up the pitch to equalise.
“It meant the tie went to penalties and we unfortunately missed a few of ours to go out of the competition.
“But there were a lot of positives and it was a good all-round display – we looked in control before the elements made everything a bit frantic.
“That was out of our control, though, and I was pleased with the commitment shown by the boys and the fact they played some really nice stuff.”
Pompey: Pitman; Setters, Kaba, Cadman, Rew; Jewitt-White, Bell; Dawson (Bridgman 35), Lee (Gifford 80), Brook (Hughes 71); Anderson