The visitors were the better side in the first half with Matt Tubbs missing a host of changes, although Joe Jacobson came closest to scoring when he rattled the crossbar with a well-hit shot.
Wanderers improved and saw Fred Onyedinma's header bounce just wide in the second period, but neither side could find a win to ensure a second consecutive stalemate for the Blues.
Gareth Ainsworth made two chancges to his starting line-up, with Matt McClure and Hogan Ephraim taking the places of Matt Bloomfield and Aaron Holloway, while Peter Murphy captained the side and sported a head bandage having been whacked in last week’s 0-0 draw at Mansfield.
The visitors started well and applied some early pressure to the Wanderers’ backline, who coped well with a couple of dangerous deliveries into the box. Matt Tubbs had the first real sight of goal when he raced through one-on-one only for Aaron Pierre to recover and block his tame shot, before the same striker saw a close-range effort saved by Matt Ingram after a corner came his way on the six-yard box.
Tubbs again had a chance when he stayed onside down the left and got his shot away, but Ingram again kept his side in it with a strong save before it was scrambled clear.
Former AFC Wimbledon man Tubbs was certainly the man to watch, and after Joe Jacobson deflected his effort wide, Jack Whatmough mistimed his header at the back post from the corner and could only send it into the side netting.
It took 34 minutes for Wycombe to register their first chance and it failed to trouble the keeper as Sam Wood sent a glancing header wide from Peter Murphy’s cross, before Ingram did well to hold on to a well-hit shot from the edge of the box at the other end.
For all of Pompey’s dominance, they were almost behind the break after a fine move from the hosts released Joe Jacobson on the right-hand side of the box, but his swerving effort crashed against the crossbar as the half drew to a close.
The start of the second half saw chances hard to come by for both sides but Wycombe showed gradual signs of improvement and started to stretch a Pompey defence who’d had a fairly comfortable ride up til then.
The introduction of Aaron Holloway added new life to the attack and after Pompey just about scrambled clear after McClure and Onyedinma tried to turn goalwards, Fred had another chance when his header from a cross bounced agonisingly wide with the keeper beaten.
Paul Jones later dropped a corner at the feet of Alfie Mawson but got his body behind the defender’s effort to force a corner as the Blues looked the more likely to find a late winner, but volleys from Sido Jombati and Marcus Bean in stoppage time as the visitors held on for the point.
Wycombe remain unbeaten in 11 matches and keep their place in the top three, just two points off the 55-point target set in the summer.
Wycombe: Ingram, Jombati, Jacobson, Mawson, Pierre, Bean, Murphy, Wood, Onyedinma, Ephraim (Holloway 67), McClure (Craig 79).
Unused subs: Richardson, Rowe, Bloomfield, Senior, Kretzschmar.
Portsmouth: Jones, Passley, Butler, Whatmough, Chorley (Devera 88), Robinson, Dunne, Wallace, Hollands, Taylor, Tubbs (Ertl 90).
Unused subs: Poke, Chaplin, Atangana, Barcham, Westcarr.
Ref: Andy D’Urso
Attendance: 5,829 (1,550 from Portsmouth)
Winning 50/50 Number: 133503
Prize Money: £803.00