In-form Bayern Munich hitman Robert Lewandowski has been labelled the world's best striker by Borussia Dortmund legend Karl-Heinz Riedle ahead of Sunday's Der Klassiker.

Lewandowski has been in irresistible form in recent weeks, plundering an astonishing 10 goals in his last three appearances as Bayern continue to sweep aside all-comers both at home and abroad.

The Poland forward, who swapped Signal Iduna Park for the Allianz Arena last year, has helped Pep Guardiola's team to 10 straight wins in all competitions since their defeat to Wolfsburg on penalties in the Super Cup.

And ex-Germany striker Riedle - who won the 1996-97 Champions League and two Bundesliga titles during his four-year spell with Dortmund - has hailed the quality of Lewandowski, 27, ahead of the top-versus-second clash in the Bundesliga.

When asked to compare Lewandowski and Dortmund's own prolific forward, Pierre-Emerick Aubameyang, Riedle told Omnisport: "Robert Lewandowski is just an exceptional player, whether or not he plays at Bayern Munich.

"In his position, I think he is probably the best player in the world. He hardly has any weaknesses, he is powerful in the air. He just holds on to the ball like no one else.

"He isn't that fast like Aubameyang, that's the difference. Lewandowski is just another type of centre-forward than Aubameyang.

"In my opinion, Pierre-Emerick is more of a counter-player than Lewandowski."