DPA/Rio de Janeiro

When Barcelona sporting director Andoni Zubizarreta announced at the presentation of new signing Ivan Rakitic last week that the club had already identified their new central defender - but had to wait for the World Cup to end to announce the signings - Barca fans’ imaginations began to run wild.

Which teams were left in and how many of them had centre-backs who Barcelona were now poised to sign? 

Most believe Netherlands’ Feyenoord defender Stefan de Vrij and his teammate Bruno­Martins Indi are the most likely candidates but the man most Barca fans want, especially after Friday’s winning goal against France, is Mats Hummels.

The Borussia Dortmund defender was the toast of Germany, Twitter and the ‘central defenders union’ after his performance in the Maracana - the latter delighted that in the first two quarter-finals of the 2014 World Cup there were only three goals and they were all scored by defenders.

Queens Park Rangers midfielder Joey Barton took to social media to tweet: “If David Luiz is worth 50mn euros then how much is Mats Hummels worth?” Luis was to prove his worth later on Friday night as another of the scoring defenders at this World Cup in Brazil’s 2-1 over Colombia.

Hummels’ goal had been crucial for Germany and it had been his second in a tournament that he is increasingly dominating.

“We are working very hard together in the defense. You won’t win the Cup if you concede two goals each game,” he said after another clean sheet against the French.

In the 2010-11 season Hummels and defensive partner Neven Subotic guided Dortmund to a then Bundesliga’s best defensive record when they conceded just 22 goals in an entire season winning the title.

Dortmund’s defence has not been as briliantly wáter-tight over the last three season but it has been the strong base on which Germany have built their fine campaign.

And in the semi-final next Tuesday in Belo Horizonte they will not have to face the hosts’ greatest attacking threat, the injured Neymar. Good in the air, as he showed scoring the goal against France, quick across the ground and good with his feet Hummels has emerged as the competition’s leading centre-back.

Even Joachim Loew is reluctantly convinced. He came into the tournament planning to combine Per Mertesacker presence with the pace of Jerome Boateng but Hummels is playing too well to ignore.

With a buy-out clause set at between 25 and 30 million euros, and a commitment to Borussia Dortmund who have already lost one vital player this summer with Roberto Lewandowski moving to Bayern Munich, Hummels appeares to be staying put.

The 25-year-old is one of the few players who started his career at Bayern as a schoolboy and then switched to Dortmund.  “Der Kaiser” his admirers were calling him on Friday night as Barcelona supporters mourned the fact that their mystery central defender aquisition is unlikely to be Hummels.

How they would love to take the defender who out-jumped Real Madrid’s Rapahel Varane at every corner, and most importantly for the goal, and put him in a Barcelona shirt for next season.

Hummels will leave the World Cup with more goals than Cristiano Ronaldo and if Germany can take two more big steps, then maybe he will leave with a World Cup winners’ medal.