Arsenal surrendered top spot to Manchester United at the summit of the Premier League as resolute Portsmouth held out for a goalless draw at Fratton Park on Wednesday.
The Gunners never really broke into their normally extravagant stride against a Pompey defence perfectly marshalled by Gunners old boy Sol Campbell and Sylvain Distin.
It was the first time Arsene Wenger's side have failed to score in 19 Premier League games this season and William Gallas' late miss apart there was largely little to suggest they would break that deadlock during the 90 minutes.
Wenger accused Portsmouth of employing negative tactics.
"I must say Portsmouth didn't play at all in the second half. They didn't come out at all, they just defended. It was surprising to see them just making the numbers with 10 at the back," said Wenger.
"It was difficult because they had an experienced defence and their midfield was highly focused on defending and they had just Kanu up front."
Pompey boss Harry Redknapp defended his team's approach.
"What are you supposed to do when you haven't got the ball? You can't attack if you haven't got the ball and it is very difficult to get the ball off Arsenal," said Redknapp.
"Were we supposed to open up against them and get ripped to pieces? Is that what the game is about for us?"
Arsenal remained unchanged from the victory over Tottenham at the weekend with Wenger reluctant to throw fit-again Robin Van Persie into the fray.
Portsmouth early approach was evident by Redknapp's teamsheet as he handed only a second league start of the season to Richard Hughes, himself a product of the Arsenal academy, in a clear bid to collapse play in the middle of the park.
There was also a recall to the starting line-up for Kanu after his death of his father just two weeks ago and the Nigerian was one of three former Arsenal favourite lining up for the home side.
Emmanuel Eboue had Fratton Park temperatures running high early on as he outstripped Hermann Hreidarsson before exchanging passes with Emmanuel Adebayor and shooting aggressively over.
Portsmouth's confidence grew as the half wore on.
Benjani should have done better when released by Kanu but the Zimbabwean failed to pick out any of his teammates after being left to go alone down the byline.
Niko Kranjcar was unlucky to see his fine drive drift just wide after the Croatian had accepted a pass from Sulley Muntari to turn Bakary Sagna and set-up the shooting opportunity.
Arsenal though always present a goal threat and Portsmouth's failure to convert their period of dominance almost cost them as Tomas Rosicky turned back onto his right-foot on 37 minutes and sent David James sprawling across his goal.
The second half began in similar fashion as Aleksander Hleb drove down the left but ignored the call of Fabregas and Adebayor to cross and instead selfishly elected to shoot high and wide into the stands.
Portsmouth then fashioned their best two chances as Kranjcar turned Sagna once more before forcing Almunia into a diving save.
Benjani then spurned the best chance of the match as he raced onto Kanu's through ball, rounded the Arsenal keeper but lost his footing.
That scare awoke the Londoners and Wenger's men moved forward hoping to steal the win.
Rosicky went close, crosses were cleared and then Gallas ballooned over from just six yards when it would have been easier to score.