When the reigning champions take on the record champions, first in the table against second, just five games before the end of the season, there is every reason to expect a memorable encounter. Tomorrow evening, Germany's top two teams, Borussia Dortmund and Bayern Munich, will cross swords in front of almost 80,000 fans at the Signal-Iduna Park.

"The rivalry between Bayern and Dortmund could develop into one similar to the one in Spain between Real and Barça," suggested FCB sporting director Christian Nerlinger in German daily Bild.

For Mats Hummels, the potentially decisive title clash takes on even greater importance. Despite his tender years, the BVB defender is the only player from either side to have appeared for both clubs during his career.

"If we win, I don't think we'll let the title slip," said the 13-times-capped German international. "If we lose, we'll be level on points, so if anything is decided by the result it can only be in our favour." Dortmund currently lead their southern rivals by three points at the summit.

"Now the season is really getting going," wrote Hummels on his Facebook page. "We've got five more Bundesliga games plus the cup final. They're all going to be difficult matches, but as a football fan I have to say this is exactly how I'd want to see it. We can all look forward to Wednesday. We're in good form, Bayern too, so I hope the game lives up to its promise."

Born in Bergisch Gladbach, Hummels moved to Munich aged seven after his father was offered a job as a youth coach at Bayern. Small wonder then that Hummels Jr. went on to don the famous red of Munich, spending ten years in the club's youth ranks between 1995 and 2005. However, the promising defender failed to make the breakthrough into the senior squad and after just one appearance for the first team, he decided to move on loan to Borussia Dortmund before signing permanently in 2009 for a fee of around €4m.

Since then the 23-year-old has gone on to become a key figure for Die Borussen, leaving Bayern to rue the one that got away. "I always said that Mats would be a great player," said his former coach and discoverer Hermann Gerland. "He wasn't just one of our best defenders, he also had a flawless character. We should never have been allowed to sell him."

To rub salt into their wounds, Hummels played a leading role in BVB's Bundesliga title-winning season of 2010/11, topping Kicker's poll for the league's best defender in the process with over 60 per cent of the vote. Unsurprisingly, his market value has soared.

"Mats was already one of the best defenders in Germany two years ago," said his partner in central defence, the Serbian international Neven Subotic. "Now he's the best by some distance."

The pair have developed into an impenetrable force at the heart of BVB's backline, which has conceded the fewest goals in the Bundesliga for each of the past two seasons. So far this term, they boast the third best defence with 22 goals conceded, behind Bayern (19) and Borussia Mönchengladbach (20).

"I'm happiest at centre-half," Hummels told FIFA.com in a previous interview. "It's where I can use my strengths to best effect and it's the position I know best." A switch to defensive midfield had been a serious consideration at the very start of his career.

Low lauds the head master
With his first-class passing, silky technique and fearsome aerial prowess, not to mention expert tackling, the 6ft 3ins Hummels has emerged as the leading candidate to take over Per Mertesacker's mantle as the German national team's defensive chief at this summer's UEFA EURO 2012.

"He's developed incredibly and built up plenty of confidence by playing so many games for Dortmund," explained Germany coach Joachim Löw. "He's a defender who doesn't commit many fouls. What's really impressive is his heading ability on long balls. He can win them at the other end of the field too. Many players jump on people's backs, but he manages to find space and win the ball."

Hummels was selected in the provisional squad for the 2010 FIFA World Cup South Africa™ but was left out of the final cut, making him all the more determined to be involved in the upcoming European finals: "I'm even more motivated now to be a part of it and make sure I become established in the national squad," he told FIFA.com 18 months ago. "EURO 2012 is certainly a target for me, but my priority is to play well for my club and help BVB be as successful as possible."

A year and a half later and the defender has made good on his intentions. After winning the Bundesliga title, becoming one of the league's most popular players and helping Germany to reach EURO 2012, it can only be a matter of time before Mats Hummels realises his next great ambition.