Pompey proved too strong for Bognor in front of a crowd 1,200 at Nyewood Lane - but both sides ended the night with positives.
The Blues would have been happy to win 4-1 while resting several of the players who will expect to be starting for them when the League Two season starts.
And Bognor can be satisfied at having given their visitors a decent test at a time when they are still a little way from being at full strength for the Ryman premier campaign ahead.
There was the usual clutch of second-half substitutions which turned the closing stages into a bit of a training session but the Rocks were still in the game at 2-1 entering the final 25 minutes.
For Bognor, the displays of two Brighton under-23 squad members, left-back Dylan Barnett and winger Jason Davis, was a real plus and the Rocks will doubtless be talking to the Seagulls about whether they might be able to take the pair on loan.
On a warm evening at the Lane, Pompey were first to go close - through Ben Close. He curled a shot just over after Bognor struggled to clear a low ball in from the left three minutes in.
Then Conor Chaplin - who was to prove Pompey’s best performer - outmuscled his marker and fired a left-footed drive inches over Billy Granger’s bar.
Chaplin was the dangerman early and forced Granger in a good low save with his legs at his near post after bursting into the box, then Curtis Main missed a rebound from a shot Granger failed to hold, but the offside flag was up anyway.
Although it was Pompey doing most of the attacking, Bognor were having their moments too and Harvey Whyte got free down the right and fired in a volley that Paul Jones held.
Barnett was at left-back for the Rocks and was impressing with some runs forward. He was one of two Brighton youngsters in the Rocks starting XI - winger Jason Davis being the other.
Main should have done better from 12 yards but hit the clubhouse roof, then Granger denied Chaplin with a splendid one-handed save when he appeared to diving the wrong way.
A Ben Tollitt free-kick from the right beat everyone in the box but eventually fell to Close, whose drilled effort was blocked as the Bognor defence continued to stand their ground.
Pompey took a 27th-minute lead when Chaplin curled a free-kick over the wall and beyond Granger’s dive - that after the young forward had himself been upended 20 yards from goal by Sami El-Abd.
A Barnett cross just eluded Ollie Pearce and James Fraser and Bognor almost scrambled home an equaliser from the resulting corner.
Whyte and Davis were linking well down the right but couldn’t unlock the Pompey defence.
Adam May was close to making it 2-0 on 41 minutes with a low shot across Granger that was just wide.
The Blues didn’t have to wait long for their second, though, as Main headed in from close range when Chaplin curled a cross that was right on his head.
The Rocks began the second period in positive fashion and Barnett tested Jones with a fierce shot after another energetic run down the left. When the corner came in, a messy scramble ended with Whyte poking home.
Pearce got up well for a header which Jones had to get down to.
Close wasted a half-chance for the Blues when a long ball was knocked down to him 20 yards out and his shot was too high.
Multiple substitutions followed for the Rocks, with Ed Sanders, Darren Budd, keeper Joe Taylor and Jimmy Wild coming on for El Abd, Fraser, Granger and Whyte.
The changes gave the Rocks a spring in their step for a while and James Crane tried his luck from outside the area, but the shot was over.
Close was denied by new stopper Taylor after dancing past a couple of challenges in the box and shooting from a tight angle.
Pompey brought on striker Michael Smith and trialist Dean O’Halloran for Chaplin and Main.
Midway through the half Smith sent Taylor the wrong way from the spot after Tollitt’s dash into the area was halted by two defenders converging on him unfairly.
Further changes followed - Dory Yates came on for Amine Lingazi for Paul Cook’s team while the Rocks brought on Daryl Wollers for Chad Field and Matthew Consaro for Doug Tuck.
May showed good close control and lashed a low shot past Taylor for Pompey’s fourth.
Bognor kept plugging away and Wild teed up Pearce for a shot but it was all along the floor to Jones.
Pearce and Beck were replaced by Will Robinson and Matt Penfold.
Wild forced a clearance from Oxlade-Chamberlain as Bognor looked for a late second.
Rocks: Granger, Crane, Barnett, Tuck, Field, El-Abd, Davis, Beck, Fraser, Pearce, Whyte. Subs: Sanders, Consaro, Robinson, Penfold, Budd, Wollers, Wild.
Pompey: Jones, Oxlade-Chamberlain, Witherington, Davies, Barton, Lingazi, May, Close, Chaplin, Main, Tollitt. Subs: Bass, O’Halloran, Scutt, Smith, Yates.
Ref: Tim Robinson (Middleton)
Bognor are in friendly action again on Friday evening when they visit Pagham. They round off their warm-up games at Horsham next Thursday.
Report by STEVE BONE
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