SOCCER/Portsmouth  0 Arsenal 0:Arsenal's title surge has been transformed into a game of catch-up. A club that had sat on top of the Premier League virtually from the start of the season, previously slipping from the summit only when others played before them, have dropped disconcertingly behind Manchester United as the end of the year approaches.

Momentum has been checked.

Against opponents who, in Lauren and Sol Campbell, included two of Arsenal's former favourites, Arsène Wenger might have departed this game perplexed that it was his side's unfamiliar inability to score that has offered the reigning champions their slender advantage.

This was the first time this season Arsenal have been shut out, the absence of Robin van Persie, suffering from a groin complaint, among others suddenly significant.

A finisher of that calibre was sorely missed here. This contest grew more frantic in its closing stages to offer Arsenal hope, though the chances were missed. William Gallas was allowed to turn on the edge of the six-yard box 90 seconds from time only for the outstanding Campbell to slide in and connect with Gallas's ankle as the Frenchman swung to shoot, the ball disappearing into the visiting support. If the visitors were unfortunate then, Tomas Rosicky's miss seconds later was rather more wasteful.

Surrendering their place at the top the last time had galvanised Arsenal in mid-November, with Reading duly dispatched on a Monday night to re-establish the Londoners at the pinnacle after a fixture-free weekend. They had been swashbuckling and untouchable at the Madejski Stadium. Here, however, their pursuit proved more awkward. Results may have remained impressive in recent weeks but the pizzazz has drained at times.

Benjani Mwaruwari, so impressive in front of goal this season, was pinned to Portsmouth's right flank as part of a quintet of blue-shirted opponents through which Arsenal would have to thread their midfield passes. Inevitably there were still occasions when the visitors were simply too slippery to handle, Gael Clichy gliding into midfield to feed Emmanuel Eboue down the flank, or Rosicky collecting deep and skipping between leggy markers before forcing David James to save.

Had Cesc Fàbregas been a foot taller to convert Eboue's cross 40 seconds in, a different tone might have been set.

Yet Portsmouth weathered those flashes and were admirably abrasive, Pape Bouba Diop and Richard Hughes, a former Arsenal trainee, snapping into tackles with glee. Wenger might have drawn comparisons with his side's worryingly becalmed first-half performance against Tottenham Hotspur at the weekend but it was Portsmouth's harrying that had suffocated their swagger. Possession was conceded too easily for comfort, with the home side relishing the visitors' discomfort. No team can feel safe when confronted by Arsenal's purring menace but Portsmouth could at least be heartened. They might even have led by the interval.

Niko Kranjcar, fed by Sulley Muntari's clever reverse pass, turned inside Bacary Sagna and squirted a shot just wide from distance that probably represented the opening half's most carefully crafted opportunity.

Hermann Hreidarsson, darting on to Kranjcar's corner but losing his footing at the last, might have done better with a free header that found only Kolo Toure's chest.

True to form, there was more urgency to the visitors as the game threatened to drift, Fàbregas busying himself in midfield and Rosicky meandering more centrally, swapping his free role with Aleksander Hleb. Yet the visitors' desire to construct the perfect goal amid the clutter was dragging them towards familiar danger: shots were passed up in presentable positions, the passing over-elaborate. Wenger, agitating on the touchline, agonised at the disjointedness of it all.

As Arsenal rushed forward in search of a lead, the home side found bite on the break. Benjani, with a header, and Kranjcar forced Almunia to save where the visitors might have sought another pass. When Nwankwo Kanu slipped Benjani through 16 minutes from time he touched the ball too heavily around the sprawling Almunia, allowing Clichy time to recover and clear. Defeat would have been disastrous. Wenger might consider stalemate almost as damaging.