Typically, when pundits talk about the great partnerships in football the focus will be down the middle of the pitch. So we’ve got the rock-solid centre-back pairings, the perfectly balanced centre-midfield duos and the deadly striking partnerships who tend to take the plaudits.

When were two wingers ever lauded for working in tandem to great effect? Even David Beckham and Ryan Giggs were lumped in alongside their central midfielders as part of a great quartet when Manchester United famously won the Treble in 1999.

That all changed in the winter of 2004 in Jose Mourinho’s first season as Chelsea manager, when Damien Duff and Arjen Robben, two left-wingers, were at the heart of a tactical revolution in the English game, despite their success spanning such a short period of time.

While the Irishman and his unlikely Dutch partner in crime were technically Chelsea team-mates for two seasons, both of which ended with the Blues claiming the Premier League title, they only played in tandem at their very best for a few short months – but that was more than long enough to make their mark.

As with many of the best partnerships, there was an element of surprise at the beginning. In fact, it seemed highly unlikely we’d actually see the two of them operating in tandem, given they ostensibly played in the same position. Indeed, when it was revealed in the spring of 2003 that Robben would be joining us from PSV Eindhoven after that summer’s European Championship in Portugal, the response from Duff was hardly the most welcoming.

‘I must admit it was a bit of a kick in the teeth after two months out to hear about it,’ said the Irishman, then sidelined with a dislocated shoulder which was disrupting an otherwise impressive first season at the club. ‘I'll just have to carry on doing what I always do and work hard – hopefully that will be okay for me. I hear Robben is a left winger but I don't play there very often so maybe I'll get a game somewhere else in the team!’

As it was, injuries – Duff’s pre-existing, Robben’s suffered at the hands of a terrible tackle by Olivier Dacourt in a summer friendly over in the States – meant we had to wait to see how things would pan out.

Chelsea had begun Mourinho’s first season without the pair by eking out victories; a 4-diamond-2 system proving to be functional but lacking flair, and there were repeated calls from the stands for Duff to be brought into the side to provide just that.

But the Irishman’s introduction, following his recovery from the shoulder issue which had dogged him the previous campaign, only had a slight impact on our attacking improvement and there were few signs of the record-setting campaign we would go on to enjoy.

It’s fair to say the Premier League title was won and lost between 23 October and 2 February. The first date marked Robben’s competitive debut for the Blues, a thrilling cameo at Stamford Bridge against Blackburn Rovers; the latter date, the return match at Rovers’ Ewood Park home, saw the Dutch winger suffer an injury which, to all intents and purposes, brought to an end any further meaningful contributions he would make to our season.

In between times, Mourinho’s side won 14 matches and drew two, with no defeats. Arsenal, our nearest challengers, could only muster seven victories during the same period of time. The Blues were setting a searing pace which few sides in Premier League history could have lived with, and Robben was at the forefront of that.

His brief performance against Blackburn served notice of what was to come, but the worry for Blues supporters was that the new boy’s return to action would come at the expense of Duff, the Irishman having established himself as the most popular signing of the nascent Roman Abramovich era but yet to show his best form under Mourinho.

There was no need for concern. The manager was quick to point out the tactical versatility Robben brought to the side: ‘I see him playing outside left, his natural position; I see him playing outside right; I see him playing together with Damien Duff, changing positions. He is a top-class player and top-class players adapt to different positions and different styles.’

Soon, pundits would be discussing the wing pairing of Duff and Robben; interchanging at will, crossing the ball to one another, bewildering full-back after full-back.

The first time the two of them started in the same Chelsea side came soon after Robben’s debut against Blackburn, when we faced CSKA Moscow away. The game’s only goal came from the Dutchman after he had linked up with Duff down the same flank, which gave an indication of just what was to come.

‘There’s two things about that goal,' revealed the Irishman years later. 'The man on the street hears 4-3-3 and thinks one winger on either side, high and wide. Well, you could have thrown a blanket over the two of us! We were over on the right side of the pitch and he played the ball to me, I returned it with a backheel and then it was a great finish by him.’

Following Robben’s introduction to the side, the Blues went on a run of scoring four goals in a game six times in the space of nine matches, a far cry from the early season form which had seen us net just eight times in our opening nine fixtures.

By the time we took on Portsmouth to close out 2004, either Duff or Robben had netted in 13 of the previous 15 matches, a record most strike partnerships would have been proud of.

It didn’t matter from which flank Duff and Robben started the game; they would soon find themselves trotting across the pitch to swap, with their different brands of wing-play providing endless questions for their opposing full-backs.

‘I wouldn’t say there are a lot of teams that play with two wingers pushed up front so it is different,” said Duff of the triple-pronged attack. ‘The manager lets us switch over when we want so I suppose we do whatever comes natural to us. It’s hard for the defenders to understand, so it’s good to have that change of style up our sleeve.‘I love playing with him and he certainly gives the team an extra dimension. I feel just as comfortable on the right as I do on the left; I’ve learnt my right leg isn’t just for standing on!’

Chelsea were running away with the Premier League title by the time we travelled up to Ewood Park in early February, when Robben scored yet another winning goal, only to have his foot broken for the second time in his short Blues career. He barely featured for the rest of the campaign as we went on to set record after record, but his impact had been keenly felt by all and sundry.

‘Robben played so well with Duffer, who was on fire, and everyone realised they could play together,’ new Blues boss, and another key member of that side, Frank Lampard told Rick Glanvill for his Official Biography of Chelsea FC. ‘People couldn’t deal with their pace and skill and they were scoring and making goals’

There were only fleeting glimpses of their brilliance the following season, and Duff departed for Newcastle United in the summer of 2006, with Robben heading to Real Madrid a year later. But in those 17 matches they started alongside each other in the 2004/05 season, they played an integral role in establishing Chelsea as a Premier League and European force to be reckoned with, as well as challenging the conventional role of wingers in English football.