Danny Cowley has warned his players they will have to work harder if they want to keep playing for Pompey.
A brace from Ronan Curtis was not enough to keep them in the Carabao Cup against Newport in south Wales.
His goals were cancelled out by Will Evans and Aaron Wildig before James Waite grabbed a winner for the League Two hosts.
And Cowley was frustrated that his side failed to work hard enough out of possession, ensuring they exited the competition in the second round.
The Blues boss said: “We’re disappointed because it was a messy performance from us, although credit to Newport, who played at 100 miles per hour.
“After weathering an early storm we got some real control in the tie and were creating chances at will – we should have been out of sight.
“But in the second half we didn’t respect the game and didn’t do the things that have allowed us to have the success we’ve seen so far this season.
"We made a lot of changes, but I’d expect the side we picked to be able to come here and win the tie or certainly produce a better performance.
“Three managers have come into our office after matches and said similar things about how we do the basics so well.
“But we didn’t do that on this occasion. We didn’t defend well enough and if you’re not willing to do the work against the ball, you won’t play in our team.
“We made a lot of changes, but I’d expect the side we picked to be able to come here and win the tie or certainly produce a better performance.
“Defending is an 11-man job and it doesn’t matter what you give the team offensively, you’ll find yourself out of the team if you don’t do that.
“Some of the younger players found things difficult, but the senior guys didn’t help them as well as they could have.”
Zak Swanson went off injured in the first half, while Cowley also provided an update on Louis Thompson, who suffered a broken leg at the weekend.
He said: “Zak just got some really nasty stud marks right up the top of his shin and couldn’t run it off, which disrupted our plans.
“Louis will see a specialist on Wednesday and we’ll see what that shows. There’s some low level ankle damage, but we need to wait to see what the next course of action is.”