Kanu seems to have forged a career out of rolling back the years.
Still, it appears old dogs can be taught new tricks after all.
For nowadays the veteran has also unearthed a useful penchant for upsetting Cardiff City.
As if Pompey fans needed reminding, it was Kanu who netted that FA Cup final matchwinner in 2008.
The Bluebirds won’t forget it either.
After all, when Sol went up to lift the FA Cup they were also there.
They were emptying Wembley in their masses but nonetheless there was still a Cardiff presence for the moment which has gone down in Pompey folklore.
So how fitting it was that on Saturday the main protagonist from that wondrous occasion was back doing what he does best – scoring goals and taunting Cardiff.
Kanu was not involved in either fixture against then-manager Dave Jones’ side last term, both of which resulted in Bluebird triumphs.
On Saturday, however, he was back for his first appearance against them since the Cup final – and back to ruin those Welshmen’s day out for a second time.
Of course, the veteran striker’s appearance on this occasion was to span a mere 13 minutes.
Steve Cotterill’s decision to drop him to the bench in favour of granting Erik Huseklepp a full debut was surely one applauded by all Pompey fans.
No disrespect to Kanu, you understand, it was just the desire to see the Norwegian international permitted a start following his eye-catching Bristol City cameo.
But with 77 minutes on the clock and the hosts one goal down, it was the former Arsenal man who Pompey’s boss pinned his hopes on.
Off came Luke Varney and in his place entered Kanu for his first kick against Cardiff since May 17, 2008.
If that sight wasn’t enough to unsettle the away fans, they were soon left cursing his name. Again.
It took just three minutes for him to make the difference.
Tal Ben Haim flung in a teasing, curling cross from the right-hand side and there was Kanu to stoop to head home at the far post.
It was Pompey’s fourth goal in six games so far this season, a statistic which is growing ever-more concerning.
Still, after a gap of three years, three months and 10 days, Kanu had once again etched his name on the scoresheet against Cardiff City.
It seems only yesterday when he struck at Wembley, then again there is a timeless essence to the former Nigerian international.
When asked to pinpoint Kanu’s age in his post-match press conference, Cotterill emitted a smile and politely declined to get involved.
Fair to say, though, two of the recent striking arrivals at Fratton Park are at the other end of the playing spectrum in terms of age.
Marko Futacs, for instance, is 14 years his junior, while the fresh-faced Huseklepp appears far younger than his actual 26 years of age.
Kanu’s old pal Benjani Mwaruwari is back on the scene, though, renewing a long-standing friendship struck up during the ex-Manchester City striker’s last spell with the club.
Regardless of such striking rivals, at the age of 35 he remains a class act, especially when Cardiff happen to stumble across his path.
And though he may currently be sliding down the pecking order, Saturday was another gentle reminder how the old master is not finished yet.
Not that he should have had such a key impact.
By the time Kanu entered the field of play, the Blues could have been well clear.
It would be unfair to claim Cardiff netted against the run of play when Andrew Taylor crashed home a well-worked 71st-minute goal.
Nonetheless, a chunk of good fortune had consistently allowed them to preserve their clean sheet.
Joel Ward’s 21st-minute cross rattled the crossbar with keeper David Marshall in all sorts of trouble during the hosts’ best moment of a dour first half. After the break, Greg Halford unfurled a 30-yard screamer after being teed up by Liam Lawrence’s free-kick, only to watch it cannon against the post.
The defender then saw a header cleared off the line by Robert Earnshaw, while the trick was repeated by Peter Whittingham not long after to deny substitute Benjani.
Cardiff may point to Darcy Blake striking the post early on as evidence of this being no one-man show.
But as the second half progressed there was a feeling this wasn’t going to be Pompey’s day. Sure enough, Earnshaw fed Craig Conway and he gently rolled the ball into the path of overlapping Taylor.
The left-back did the rest with a clinical shot on the run which gave Jamie Ashdown no chance as it settled into the far corner.
It was a rare moment of quality in a fixture which, up until that point, was proving a disappointing affair.
The first half, in particular, was abject viewing for another low Fratton Park crowd, this time numbering 14,354.
The woodwork may have been rattled a few times and the ball hacked off the line on a couple of occasions but don’t let that paper over the cracks.
The keepers were rarely tested and a lethargic Pompey looked a shadow of the side which excelled against Reading in their last Fratton outing.
Cotterill later put it down to over-training, apologising to fans afterwards for his oversight and accepting full responsibility.
Whatever the reason, it was a below-par display which will certainly not get supporters flooding back through the turnstiles.
As for Huseklepp, his eagerly-awaited debut foundered as he struggled to make an impact as a second striker.
Instead he was substituted on 61 minutes, having been switched to the left flank after the half-time interval at Fratton Park.
Not that he was alone in producing an unsatisfactory performance.
David Norris gave his worst display in a Pompey shirt since his arrival in the summer, Lawrence is still scratching around for form, while Varney was anonymous.
And so it was left to Kanu to level matters on 80 minutes.
It was only his ninth goal since that famous bundle over the line at Wembley almost three-and-a-half years ago.
How Cardiff really must curse the very mention of his name.