Mbia scored with a back-heel in the first leg of their Europa League semi-final against compatriots Valencia CF on 24 April 2014 in a 2–0 home win. In the second leg on 1 May, he scored the winning away goal with a header in the fourth minute of added time to take Sevilla into the final. Sevilla subsequently won the final in a shootout against Benfica at the Juventus Stadium in Turin on 14 May, with Mbia converting his penalty kick after the match had ended 0—0. On 3 June, Mbia was selected in the 18-man Europa League "Team of the Year" along with teammates Ivan Rakitić, Nicolás Pareja and Beto. At the LFP Awards, he was a nominee for the league's best African player, alongside the Granada CF duo of Yacine Brahimi and Youssef El-Arabi.
On 31 August 2014, Mbia rejoined Sevilla on permanent basis. He scored his first goal of the new season on 18 September, heading in a cross from Gerard Deulofeu as Sevilla started the defense of their Europa League title with a 2–0 win over Feyenoord. Mbia netted a brace as Sevilla earned a comfortable 4–1 victory over Deportivo de La Coruña at the Ramon Sanchez Pizjuan stadium on 5 October.
On 2 June 2014, Mbia was included by Cameroon manager Volker Finke in the final 23-man squad for the World Cup in Brazil. The team were eliminated after losing all of their group games amidst a bonuses dispute that led to Mbia replacing Samuel Eto'o as captain of the national team.