On 4 July 2013, Aubameyang joined 2012–13 Champions League finalists Borussia Dortmund on a five-year contract. He made his competitive debut for his new club on 27 July 2013 against Bayern Munich in the DFL-Supercup, replacing Jakub Błaszczykowski for the last 18 minutes of Dortmund's 4–2 victory, assisting Dortmund's final goal, scored by Marco Reus. On 10 August, Aubameyang made his Bundesliga debut and scored a hat-trick against FC Augsburg, including a goal from his first shot in the league. In the process, Aubameyang also became the first Gabonese player to appear in the Bundesliga. On 27 November, he scored his first Champions League goal in a 3–1 win against Napoli in the group stage of the 2013–14 competition. He later took a penalty against 1860 Munich that propelled Dortmund into the next round of the 2013–14 DFB-Pokal, finishing the year with 13 league goals and 16 goals in all competitions.