It's only been three weeks since the summer transfer window closed, yet rumours of Robert Lewandowski leaving Bayern Munich next summer are already beginning to resurface.

The 29-year-old, who has already scored seven Bundesliga goals this season, is reportedly "obsessed" with the idea of joining Real Madrid.

Lewandowski is said to have grown frustrated in Munich and went as far to criticise his club during the summer for their strict transfer policy.

"Bayern will have to come up with something and be creative if the club wants to keep bringing world-class players to Munich," he told Spiegel Online.

"If you want to compete at the top, you have to have those kinds of quality players.

"To this day, Bayern Munich have never spent more than around €40 million for a player. In international football that has long since been more of an average than a peak price."

Bayern boast a world-class squad - undoubtedly one of the best in the world - yet their transfer record stands at a meagre £37.5 million.

How the Bavarians have managed to stay competitive in both the Bundesliga and Europe with such a tight budget is pretty incredible.

But Lewandowski wants more, and according to German outlet Sport Bild, he's taken necessary steps to force a dream move to Real next summer.

Bild claim the Polish striker has started learning Spanish no less to convince Bayern that he's serious about leaving.

It's a somewhat risky and premature move from Lewandowski if true, but if his heart is set on moving to he Bernabeu next summer, it would be pretty hard to stop him.

Bayern would stand to make a huge profit by selling Lewandowski to Real, having signed him from Borussia Dortmund on a free transfer in 2014.

Given his contract at the Allianz Arena expires in 2021, the Poland international could command a fee in the region of £80 million if Bayern so demanded.

There's no doubting he would represent an upgrade on Karim Benzema, too, who is a world-class striker in his own right but nothing compared to Lewandowski.

Lewandowski has scored 30 league goals in each of the last two seasons, whereas Benzema, 29, has never managed more than 25 in one campaign.