In the summer of 2013, Soriano was appointed Red Bull's new captain. He scored a hat-trick in their UEFA Europa League play-off first leg against VMFD Žalgiris Vilnius, a 5–0 victory on 22 August. In his team's first match in the group stage, on 19 September, he added another three to help to a 4–0 home defeat of IF Elfsborg. In the round of 32, he grabbed a brace in a 2–0 win at AFC Ajax, and despite the team exiting in the next stage, he was the tournament's top scorer with eight goals, only the second Spaniard to do so after Rayo Vallecano's Bolo in 2000–01.