On 26 July 2013, Kießling signed a contract extension with Leverkusen, committing himself to the club until 2017. His first goals of the 2013–14 season came in the first round of the DFB-Pokal on 3 August 2013, scoring in both halves as Leverkusen defeated Regionalliga side SV Lippstadt 08 6–1. In the first match of the Bundesliga campaign, Kießling scored his side's opener in a 3–1 defeat of Freiburg. On 14 September, he scored twice in the second half to give Leverkusen a 3–1 win over 10-man Wolfsburg. With his strong start to the season along with Sidney Sam and Son Heung-min, the trio were compared to the Stuttgart's "Magic Triangle" of the mid-1990s, consisting of players Krasimir Balakov, Fredi Bobic and Giovane Élber, who were known for terrorizing Bundesliga defenses and scoring many goals.