English FA Premiership/ Portsmouth 1 Wigan 0: Maybe, as with Harry Redknapp's extensive years in management, it is a question of experience. How else to explain Portsmouth's newly redoubtable defence, the only one in the Premiership, nay, all of England, not to concede this season?

Given Alexandre Gaydamak's bounty, Redknapp's splurge on 10 players was utterly predictable, but Portsmouth's defensive record underpinning their improbable second place could hardly have been expected.

Their manager did not anticipate it, neither did he explain it. "I've never had teams that keep clean sheets," he said. "I've had teams that scored a few and let in a few."

Fratton Park is in fantasyland at the moment, with Portsmouth standing north of Arsenal by eight points and Liverpool by six. For a heady two hours they were atop the Premiership pleasure dome.

"We're going to win the league," chanted the fans after Benjani Mwaruwari's bolt from the blue shortly after the interval.

The surreal atmosphere deepened midway through the second half with choruses of "Linvoy for England". No, not David James or Sol Campbell, two veteran lions, but Linvoy Primus, aged 33 this Thursday and a veritable loyalist at Portsmouth after six years. Primus hardly made a mistake against a resilient Wigan, which is more that can be said for James and Campbell who, true to their nature, made a large blunder apiece.

No one, surely not even Primus himself, expected to be part of Redknapp's so-called revolution. Signed from Barnet during the short-lived Tony Pulis regime, the defender, according to Redknapp, "was probably looking for his next club when I became manager here".

Redknapp likes the arm-round-the-shoulder approach, as he explained about his treatment of Benjani, Portsmouth's £4.1 million signing, who experienced a distinctly difficult acclimatisation to English life this year.

"I keep telling them how good they are; that's the way I am," said the manager. "I told him the crowd loved him because he works hard. His confidence didn't go."

It must have been a very near thing, because Benjani cut an increasingly forlorn figure until his first goal in late April at Wigan on Portsmouth's "great escape" day.

His goal on Saturday, his first at Fratton Park, radiated confidence. He took Campbell's booming header, edged past Fitz Hall and clipped a shot with the outside of his boot in off Chris Kirkland's far post.

There was plenty more time to ponder Portsmouth's defensive miracle. Amid increasingly harum-scarum scenes, Noe Pamarot's underhit back-pass let in Wigan for a corner, taken by the highly impressive Antonio Valencia. James rushed out, utterly missed the ball and sent two team-mates crashing to the floor.

In injury-time Campbell let the ball roll backwards, letting in Paul Scharner to toe beyond the goalkeeper, but somehow James scrambled back to smother. This was not pretty stuff by Portsmouth, but it was effective. Just.

• Guardian Service