If all there was to Harry Redknapp was a quick wit and an easygoing manner, he would not have lasted two minutes in this sport, let alone to the age of 61. There is a saying in sport about where nice guys finish and it is not at Wembley in May or in a respectable position in the league.

The familiar line is that Redknapp is treated generously by press and public because he is good company and a lovable rogue, but that analysis is as shallow as the suggestion that his teams are solely about acumen in the transfer market and the throwing together of disparate elements in the hope that it works.

Tony Mowbray, the manager of West Bromwich Albion, who are pushing for promotion to the Barclays Premier League, knew why his team lost and there was nothing random about it. “Portsmouth have built their team on strong defence,” he said. “They are sixth in the Premier League on the back of defensive organisation. I take heart that not every team up there is as solid as they are.”

Hear that? Discipline, tactical acumen, order - the sort of qualities often overlooked in Redknapp, masked by a one-liner or a funny story. And, yes, it makes him a popular figure, but that will get a man only so far. Had Portsmouth lost at Wembley on Saturday, had Redknapp thrown away perhaps the best opportunity he will have to lift a leading trophy in English football, he could not have walked away from the calamity with a shrug of his shoulders and a quip.

There would have been a moment of reckoning and it would have been noted that, when it mattered, the Portsmouth manager could not rise to the occasion. And while no one would say that Saturday’s win was a peak performance – the match being won by a scrappy goal from Kanu after 54 minutes – Portsmouth kept it tight, stood up to a lively first-half assault from the Coca-Cola Championship team and improved considerably after half-time when Redknapp made tactical adjustments.

He had a lot to lose, taking over Portsmouth, leaving for Southampton, their fierce rivals, and then going back. Now the money made available by Alexandre Gaydamak, the owner, has begun to have an effect, some may believe that Redknapp had it easy. Nothing could be farther from the truth. Reflecting on his time at the club, he spelt out the journey he has taken.

“The first time here, when I was director of football and Milan Mandaric [the chairman at the time] asked me to take over as manager, I refused,” he said. “I really didn’t want it. They had finished just off the bottom five years running – twentieth, nineteenth, eighteenth, twentieth, seventeenth – and I thought, ‘No way do you turn this lot around.’ But he talked me into it and we won promotion as champions. Then I went to Southampton, left a really good team behind and when I returned they had a terrible one.

“First day at the training ground Dejan Stefanovic, who was the captain and a good player before I left, said to me, ‘Gaffer, you’ve got no chance here. This is the worst team I have seen. You must be mad.’ After one morning’s training I realised he was right. I thought, ‘What am I going to do with this lot?’ Where they found some of them, God knows. It was a poor side, bottom of the league and rightly so.

“I remember going to Wigan Athletic, knowing that if we had gone down that day it would have been hard for me to carry on. People forget, I did not come back here with everyone welcoming me, out on the pitch, arms in the air, waving to the crowd. They all say they did now, but when I walked off at Aston Villa after the first game all the banners said ‘Judas bastard’, stuff like that. If I had not got them out of relegation, they would have slaughtered me.”

And that is the side of Redknapp that is often ignored – the one in which he plays the unremarkable role of the damn fine manager, getting his head down, getting on with the job and building useful, often entertaining teams. Why? Because everyone prefers the colour and charm of ’Appy ’Arry, the cheerful Cockney cliché. And he exists, too, just not at the expense of the other guy.

Still, for lovers of light entertainment, here is a true Harry story from the week before the semi-final. He gets a letter, the sort that managers receive all the time. Bloke says he follows Portsmouth home and away with his wife, been to every round of the FA Cup but can’t get a ticket for Wembley. Doesn’t know how the internet works, can’t get to the ground as he lives in Wales.

Harry, being Harry, takes him at face value, phones, leaves a message, says he will call back. It is April 1, but Harry doesn’t remember that. When they finally speak, the bloke says he has been rowing with his mates for two days, thinking it was a wind-up. Anyway, Harry sorts him out. Two together, good seats, too. Now, Arsène Wenger, the manager of Arsenal, seems a charming man also, but can you imagine him doing that?

Redknapp’s secret is that he is not frightened. Not frightened to phone a supporter out of the blue in an act of kindness (because that really does open Pandora’s box with an FA Cup Final around the corner) and not afraid either to make Tony Adams his assistant, when many saw the former Arsenal and England captain as a stalking horse, a threat if things went wrong, rather than a useful colleague.

“I never worried about his presence for one minute,” Redknapp said. “I love having Tony with me. What a player he was. I want Tony to be manager here when my time is up.”

And if, because Redknapp has the confidence to put strong personalities and one of England’s greatest defenders on his staff, Portsmouth have got to a Wembley final by winning four of their five FA Cup ties 1-0, doesn’t that make him a clever old stick? If Fabio Capello were to do that he would be hailed a tactical genius; only because it is Redknapp does anyone think that it happens by accident.

How they rated

West Bromwich Albion (4-4-2): D Kiely 6 C Hoefkens 6 M Albrechtsen 6 N Clement 6 P Robinson 6 Z Gera 6 R Koren 7 J Greening 6 J Morrison 6 R Bednar 5 K Phillips 7 Substitutes: I Miller 6 (for Bednar, 60min), C Brunt 5 (for Morrison, 60), Kim Do Heon (for Gera, 74). Not used: M Danek, Pele.

Portsmouth (4-4-2): D James 6 G Johnson 6 S Campbell 7 S Distin 7 H Hreidarsson 7 P Bouba Diop 6 L Diarra 8 S Muntari 7 N Kranjcar 6 M Baros Y 6 Kanu 7 Substitutes: D Nugent (for Baros, 71min), S Davis (for Kanu, 80). Not used: J Ashdown, Lauren, P Mendes.

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