The 10 biggest betrayals in football!

#2 Robert Lewandowski-

Robert Lewandowski - The Pole who led Dortmund to win back-to-back titles.

In 2010, Borussia Dortmund signed a young Polish striker named Robert Lewandowski for a nominal amount of 4.5 million euros from Lech Poznan.

Lewandowski went on to score 103 goals in 187 games for Dortmund and was an integral part of Jurgen Klopp's young team of underdogs- helping them to win the Bundesliga twice.

At the time, the success of Dortmund was celebrated by neutrals all over the world as a story of David vs Goliath because they had bested German giants Bayern Munich, who had far more financial power and footballing clout.

However, Bayern, being Bayern did what they do best when it comes to dealing with rival Bundesliga clubs- picking off their best players.

Lewandowski - joined rivals Bayern by running his contract down

Lewandowski ran down his contract to join Bayern Munich for free and his 166 goals in 211 appearances thus far - have ensured that the Bundesliga is a "one horse league" again as Bayern romped home to 4 consecutive Bundesliga titles since.

When it had become clear that the Polish striker was not going to sign an extension, Dortmund was even open to the idea of selling him to any club outside of Germany. However, Lewandowski turned down interest from the likes of Real Madrid and Chelsea to move to Bayern Munich as a free agent.

That has got to hurt!