The triumph was seen as the breakthrough that Great Britain's top three middleweights needed to make an impact at elite level after Barker, alongside Martin Murray and Matthew Macklin, had previously missed out on their attempts to win a world title.
A mammoth domestic showdown between Barker and Murray would have been the natural progression for both fighters had it not been for former champion Felix Sturm being installed as the mandatory challenger for the 31-year-old's belts, leaving the prospect of an all-British world title clash up in the air.
After his courageous performance against Geale back in August, Barker will go into the Stuttgart encounter as the marginal favourite to defend the IBF strap. But while the Londoner displayed his durability in New Jersey, he will have to show a different kind of strength to ensure that he returns to these shores with his world title still intact.
The general consensus is that given the contrasting stages of their career, Barker probably has the edge over Sturm in terms of quickness and confidence, but it would be foolish to discount the factor of home territory that plays into the hands of the challenger.
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Competing regularly in Germany has arguably helped to prolong Sturm's career over the past two years, with the 34-year-old being awarded a debatable decision against Macklin in 2011, while he was fortunate to earn a draw against Murray six months later.
Home advantage failed to assist Sturm in overcoming Geale in the autumn of 2012, but when factoring in that a judge scored the fight 116-112 in favour of Sturm when his colleagues deemed the encounter heavily in favour of the Australian, it gave an indication of the kind of performance that you have to deliver to earn success away from home.
When Barker fought Geale, both men were competing on neutral ground in front of a less-than-capacity crowd, but when the Brit steps into the ring on Saturday night, he will be doing so in front of 7,000 passionate German supporters who will want to ensure that Sturm continues his career into 2014.
While Barker will enter the squared circle on a level playing field, he will subconsciously know that he will have to put on the performance of his career if he is to get the better of his more experienced opponent, with a stoppage potentially his best chance of regaining his title.
The Brit has several strategies available to him to come through this fight, but if Barker is floored like he was in Atlantic City, it will be highly improbable that he can wins on points, which could result in 'Dazzling' fighting on the back foot during the opening stages of the encounter.
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However, if Barker places enough belief in his speed to beat Sturm to the punch, he could do enough to take the opening rounds by a clear margin, leaving the German to chase the fight going into the middle rounds and closing stages.
Saturday's bout will be the 45th of Sturm's professional career, and he visibly slowed during the final moments of his loss to Geale, which could leave open the possibility of Barker forcing the late stoppage of the match, and the 34-year-old's career.
Barker has spoken confidently about defeating Sturm, but talking is one thing, and boxing is another. Surviving that gut-wrenching body shot from Geale midway through their August contest would had given Barker a sense of invincibility, but he has to remain level-headed going into what is still a dangerous fight.
Sturm has never been the biggest of punchers, but Barker must avoid thinking that he can take everything that his opponent has to offer because he can't allow the German to develop any sort of foothold in the fight or give the home supporters any further encouragement to raise the decibel level inside the Porsche-Arena.
Mentality is going to play a huge part in this bout, and if Barker employs a calculated, positive gameplan to the letter, he will win this fight. However, he must remember that Sturm has only lost three times in nearly 13 years, and the former middleweight king can't be discounted with any degree of confidence as he tries to extend his time in the sport.