BERLIN • Bayern Munich launched their bid to win a historic fourth successive German Bundesliga title on Friday with a 5-0 rout of Hamburg, as new signing Douglas Costa shone on his league debut.
Robert Lewandowski, Medhi Benatia and Thomas Mueller, who netted twice, grabbed Bayern's first four goals, and Brazil winger Costa added the fifth.
Costa, whom Bayern coach Pep Guardiola has said can be the best winger in the world, showed why the champions paid Shakhtar Donetsk 30 million euros (S$46.8 million) for him in July.
The 24-year-old chested down a long pass before firing in a cross which led to Bayern's third goal, then scored with a crisp left-footed shot in the 87th minute.
"He's a superb player, I understand him very well already and he's just going to get better with each game," was Lewandowski's verdict on Costa.
Guardiola, in his third and final year of contract, said: "It was tough in the first half, because Hamburg defended with six players, but we did better in the second half.
Hamburg, who only avoided relegation last season by winning a play-off for the second year running, had their share of early chances as ex-Tottenham Hotspur midfielder Lewis Holtby fired a fourth-minute shot straight at Bayern goalkeeper Manuel Neuer.
But after Benatia headed home in the 27th minute, the floodgates opened for Bayern as Lewandowski (53rd minute) and Mueller (69th and 73rd) piled up the goals before Costa's late goal sealed the rout.