However, Harry Redknapp's men were much improved this time and would have taken all three points but for the width of a post when Richard Hughes struck the upright with nine minutes left.
Reading, who have already surpassed all expectations on what has been a remarkable first season in the top flight, promised much - but were unable to find a finishing touch after spells of dominance.
Both these sides still harboured European ambitions, with even seventh in the Premiership likely to secure a place in the UEFA Cup next season.
• Coppell not dreaming of Europe
It had been a positive start to the match by the hosts, who had been given some extra time off during the break in Premiership action by manager Steve Coppell.
A poor back-header by Glen Johnson put Royals striker Leroy Lita away into the left side of the area.
However, the ball would not drop for him, with Linvoy Primus - against his old club - and Sol Campbell eventually combining to scramble it behind for a corner.
There was an opening for Pompey after eight minutes.
An attempted headed clearance by Michael Duberry dropped to Arnold Mvuemba at the edge of the box, but the on-loan Rennes midfielder - making his first start for Pompey - drilled his shot just over the top-right corner.
The match was delicately balanced, with both sides not afraid to go forwards.
A deep cross from Stephen Hunt out on the Reading left was almost turned in by Dave Kitson, who arrived at speed in the six-yard box.
Pompey goalkeeper David James, though, showed quick reflexes to collect the low ball first.
Glenn Little then headed wide at the near post from another left-wing centre as Reading upped the tempo.
However, it was Pompey who came close to taking the lead on 23 minutes when Gary O'Neil's curling 20-yard volley dipped just inches over the crossbar.
After such a positive opening to the match, both teams were then guilty of giving away possession following some promising build-up.
With 12 minutes to go before half-time, there was a break in play as Hunt received treatment to his ankle after an awkward fall. The Reading forward was, though, soon back in the action.
James Harper tried his luck from a full 25 yards, but spooned his shoot well wide.
As half-time loomed, it needed a brilliant saving tackle from Campbell to deny Kitson - just when the Reading striker looked set to pull the trigger in the six-yard box.
As the match entered the final 20 minutes, a promising run from Kanu run down the Reading right was blocked by Nicky Shorey and the foul was signalled by the assistant.
After a short delay referee Steve Bennett showed a yellow card to Duberry, presumably for protesting the decision. Niko Kranjcar struck the resulting 22-yard free-kick just wide.
Pompey almost snatched a winner in the 81st minute when a fine first-time strike from midfielder Hughes, some 25 yards out, came back off the right-hand post.
Victory would not have been unjust for the visitors against a Reading side who on a rare occasion this season failed to find top gear.
As it was, a point maintains the hope of both clubs to stay in contention over the closing months of the campaign for what would be a dream UEFA Cup spot.
Coppell not dreaming of Europe
Manager Steve Coppell maintains Europe is not on Reading's 'radar'.
The Royals and today's opponents Portsmouth remain in the tussle for a place
in the UEFA Cup next season after a goalless draw at Madejski Stadium.
Seventh place could be good enough to qualify depending on the outcome of the
FA Cup final.
Coppell, though, insists it is something he and the squad are not making their
sole focus.
The Reading boss said: 'We are not equipped for Europe and it is really not
on our radar at the moment at all.
'The only way we exist is by trying to win the next game. That is our
mentality.
'We do not set targets about where we want to be and what we want to do.
'All we are about is winning the next game.'
The Royals boss is also wary of how a UEFA Cup campaign has in fact been
detrimental to other clubs in the past, such as Ipswich and, to an extent this
season, West Ham.
Coppell added: 'Europe is too heavy a load for us at this stage in our
development. Whether we do develop, only time will tell.
'Certainly at the moment, it would not be good for us - as [former Ipswich
manager] George Burley told me last week.'
Reading have, nevertheless, already surpassed all expectations on what has
been a remarkable first season in the top flight.
The home side promised much but were unable to find a finishing touch after
spells of dominance.
Portsmouth would have taken all three points but for the width of a post when
midfielder Richard Hughes struck the upright with nine minutes left.
'If that had gone it, it would have been a travesty, but such is football,'
said Coppell.
'From an effort and work-rate point of view, I thought our performance was
good.
'They came to do a job and did that well. We found it difficult to break them
down at times.'
Portsmouth have seen their own form falter following what was a brilliant
start to the campaign, winning only one of the last nine Barclays Premiership
outings.
Today's battling goalless draw halted a run of two straight defeats.
Manager Harry Redknapp said: 'With a bit more quality on our final ball, we
could have killed them off in the second half.
'It is not an easy place to come, so I was pleased with our approach on the
back of a poor away game last time.'
For the Pompey boss, qualification for Europe remains very much a positive
target.
However, Redknapp knows all too well those outside the top four have to be
grateful for any scraps.
Redknapp said: 'I would like it - but is may well be out of our radar too.
'If you look at the league, Bolton, who are fifth, have gone to Old Trafford
and been smashed to pieces.
'The top four are just on another planet. There is such a gulf. The gap is
enormous. For the rest of us, on any given day, anything can happen.'
Redknapp added: 'I would always have a go at anything - and would love the
opportunity to play in Europe with Portsmouth, if we could do it.
'We have tried to keep at it but have had some tough games.
'We want to finish as high as we can, the players have not taken their foot
off the pedal - it is just that Premiership matches are so hard to win.'
Reading 0 - 0 Portsmouth
