A crowd of more than 8,000, swelled by 1,600 noisy Pompey fans, were treated to a five-goal thriller with the Shrews holding on despite a spirited display from the visitors - who rallied from 3-0 down.
"We told the players before the game just to go and enjoy the occasion," said Shrews boss Turner. "We're safe and we just wanted them to go and put on a good performance.
"I thought the atmosphere was terrific and it was an enjoyable afternoon.
"We had a good start to the season in terms of performances but the results didn't come and we found ourselves at the wrong end of the table. But character was shown and we've finished 16th, and I would think we have to be very satisfied with that given all the trials and tribulations of being near the bottom of the table."
Connor Goldson headed the hosts into an early lead before Joe Jacobson's deflected free-kick doubled the advantage in the 37th minute.
Shrewsbury looked set for a convincing win when Akwasi Asante, on loan from Birmingham, made it 3-0 soon after the restart. But Portsmouth, in Guy Whittingham's first match since he was appointed manager on a permanent basis, then showed plenty of fight with goals from strikers Ashley Harris and Patrick Agyemang to set up a nervy finish for Turner's team.
"We dominated for long periods and then perhaps just that lack of experience showed," added Turner.
"At 3-0 we should have been taking the sting out of the game at times but we were still knocking it into the front men.
"As a result, they were counter-attacking and we nearly paid a heavy price for it. But the enthusiasm, the hard work, the energy again we showed for most of the game was first class."