Hamšík provided an assist for Gökhan Inler's opening goal against Villarreal on 7 December and then scored the decisive goal, helping Napoli to a 2–0 victory in Spain. The win secured qualification to the round of 16 in a very difficult group, which included Bayern Munich and Manchester City. Hamšík helped Napoli finish the first half of the 2011–12 campaign on a high, scoring a superb goal in Napoli's 6–1 hammering of Genoa on 21 December. Hamšík also provided assists for strikes by Goran Pandev and Walter Gargano in the match. Through the first half of the 2011–12 campaign, Hamšík had appeared in 16 Serie A matches, contributing five goals and five assists. In Napoli's European campaign, Hamšík appeared in all six group stage matches and contributed two goals and one assist.