Joe Rafferty was one of just two players to remain from Saturday’s convincing league win at Shrewsbury.
And the much-changed Pompey side crashed out of the Bristol Street Motors Trophy after losing 5-2 to AFC Wimbledon on home soil.
The damage was done inside the opening half-hour, with some slack defending leapt upon by the visitors.
And Rafferty – who switched to a centre-back role for the contest – was unhappy with the team’s display.
The stand-in skipper said: “We weren’t on it and sometimes that happens when you make a lot of changes, although we don’t want to use that as an excuse.
“In previous games, the lads who have played in this competition have done really well, but it was one of those nights.
“We gave away three soft goals and there was a mountain to climb after that. We just weren’t good enough.
"I wasn’t too good and suspect that many of the lads would say exactly the same thing about their performance."
“There were a lot of mistakes that happened all over the pitch, so you can’t single one person out for the result.
“I wasn’t too good and suspect that many of the lads would say exactly the same thing about their performance.
“Now it’s important that we regroup as a team and be ready to go again for the next game on Saturday.
“The league’s our only focus now and promotion has always been the goal, although it was a good chance to go all the way and give lads a chance to play.”
There was a welcome return to action for fit-again winger Anthony Scully, who featured for the entire second half after a long spell on the sidelines.
Rafferty said: “It’s absolutely brilliant to see him out on the pitch again and he gives us another option.
“Getting him up to speed is really good and the more players we’ve got ready over the busy Christmas period, the better.”