Out-of-sorts Borussia Dortmund star Shinji Kagawa hopes to turn his stuttering season around after hailing his two-goal contribution to Japan's 8-0 rout of Tajikistan as a psychological breakthrough.

Kagawa has struggled to reproduce the scintillating form he showed after joining German champions Dortmund last summer, making an indifferent start to the new Bundesliga campaign after returning from a broken foot sustained on national team duty at the Asian Cup in January.

But fans at Nagai Stadium were treated to the full range of the 22-year-old's skills as he helped Japan rip the hapless Tajiks apart in their World Cup qualifying match on Tuesday, capping a fine performance with a razor-sharp finish in the first half and a curler from the edge of the box after the break.