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The substitute's second-half strike settled the contest at Millerntor-Stadion, where Hauke Wahl cancelled out Edmond Tapsoba during the first half.

St Pauli made the stronger start with Wahl denied on the line, but it was Leverkusen that broke the deadlock in the 25th minute.

Tapsoba was alert to turn in from close range after the hosts failed to deal with Alejandro Grimaldo's free-kick delivery.

Nevertheless, Alexander Blessin's side was level just seven minutes later, when Wahl hooked the ball in after Mark Flekken spilt a corner.

The visitors restored their advantage in the 58th minute when Poku, just on as a substitute, slotted home what proved to be the winner for Kasper Hjulmand's men.