Zárate scored from outside the penalty area to conclude West Ham's 2–0 win over Arsenal at the Emirates Stadium in their opening match game of the 2015–16 Premier League season. His deflected strike could not save West Ham from third round elimination in the 2015–16 League Cup, Leicester City prevailing 2–1 after extra time. He continued his good early season scoring form as he scored the opening goal in the "Hammers"' 2–1 victory over Chelsea on 24 October, following this up with a free-kick in a televised match against West Bromwich Albion on 29 November, a 1–1 draw.