Brian Viner: Don't you hate it when heroes change sides? But they're only doing their job

The Way I See It: Who'd have bet on Big Eck starting the 2011-12 season in charge at Villa Park? Big Ron seemed more likely

The way I see it, indeed the way most people see it, is that the Wigan Athletic manager Roberto Martinez is a fellow of charm, intelligence and integrity. That is not, however, how a minority of Swansea City fans see it. They can't really quibble with the intelligence and the charm, but for them a man of integrity would not have succumbed to the lure of the Premier League in 2009 after serving Swansea with such distinction as player and manager and promising that he would not take flight from the Swans unless compelled to do so by the board.

When he then accepted the overtures of Wigan owner Dave Whelan, and took key members of his back-room staff with him, some Swansea fans all too predictably labelled him "a Judas". During his playing career Martinez had actually spent considerably longer at Wigan than at Swansea, but that cut no ice with the fans he left behind, whose anger had not abated by the time the two clubs met in the Carling Cup last October. Hell hath hardly any fury like football supporters scorned.

On Saturday, in one of those fixtures that confirms beyond any doubt that some computers do have a sense of mischief, this season's first visitors to the Liberty Stadium, and therefore the first English team in the Premier League to play a league match outside England, were Wigan Athletic. Martinez duly braced himself for more of the hostility that was flung at him by those Swans fans visiting the DW Stadium last year. Happily, though, very little came his way. On the whole, the home crowd preferred to let Swansea's return to the big time after so long determine their emotions, and not a few of them acknowledged that the club still owes Martinez plenty. He got the welcome he'd been hoping for but had not dared to expect.

At precisely the same time, at the nearest Premier League match to Swansea v Wigan, Aston Villa manager Alex McLeish was also getting the welcome he'd hardly dared to expect, as prior to kick-off against Blackburn Rovers most Villa fans appeared to offer their support to a man who not six months ago led bitter rivals Birmingham City to a trophy. The Carling Cup was secured, moreover, at Villa's expense; Birmingham having beaten them over a two-legged quarter-final notable for its acrimony both on the field and in the stands. Who'd have bet then on Big Eck starting the 2011-12 season in charge at Villa Park? Big Ron seemed more likely.

That McLeish also led Birmingham down to the Championship last season might have been a factor in Saturday's show of appreciation, or maybe the Holte End have simply embraced the old dictum about your enemy's enemy. Blues fans hate him for taking the Villa job, so let's show him some love to annoy them even more. Or maybe the Villa faithful reasoned that there was simply no point wasting their energy by booing their own manager in the first home game of the season. Whatever, the applause offered to McLeish and Martinez on Saturday afternoon looked like proper grown-up behaviour, not a collective impulse for which football crowds are known.

Earlier on Saturday, Steve Bruce had given his usual impersonation of a man being repeatedly electrocuted, as he stood on the touchline enduring the agony of his Sunderland team losing at home to Newcastle United. This is the same Steve Bruce who grew up a devoted Newcastle fan, habitually ducking under the match-day turnstiles at St James' Park. Now he longs to see the Magpies properly mauled by the Black Cats, a mauling that was administered the other way round last October when Newcastle thrashed Sunderland 5-1 at the Stadium of Light. It must have properly ruined his weekend to see Newcastle, for the second successive season, leave Wearside with all three points.

So what are football fans to learn from Roberto Martinez leading his team into the opposition dressing room at the Liberty Stadium on Saturday, from Alex McLeish crossing the Second City and from Steve Bruce plotting Newcastle's downfall?

It is, of course, that, ultimately, managers, coaches and for that matter players are not prey to the emotions that flow down from the stands. No matter how passionately they do their job, it is just a job. As an Evertonian, I would hate to see David Moyes succeed Kenny Dalglish as Liverpool manager. I would like to think that out of respect for the Everton fans, he would never contemplate doing so. But wouldn't Arsenal fans in 1989 have ridiculed the notion of George Graham leading out the home side at White Hart Lane, had anyone been sufficiently doolally to venture it?

Supporting a football team is an article of faith, a matter of quasi-religious fervour, a lifetime commitment, however you want to put it. By contrast, managing a football team, or playing for one, is merely a contractual obligation, a business arrangement. If more supporters could get their heads round that, as a gratifying number managed to do at Swansea and Aston Villa on Saturday, football would be in a better place.