On 26 April 2014, in the Greek Cup final against rivals PAOK, Berg scored a hat-trick to lead Panathinaikos to a 4–1 victory, who won the Greek Cup as they had done in 2010. On 11 January 2015, Berg scored his second hat-trick in a 5–0 home win against Ergotelis in the Superleague Greece. On 26 January 2015, he signed a one-year extension contract, until 2018. On 8 March, in a Panathinaikos–PAOK derby, Berg scored his third hat-trick in a 4–3 home win. On 30 March 2015, after two-and-a-half years, Berg scored his seventh international goal on friendly match against Iran.