At the end of the month, Southend extended the loan deal to run until 3 January 2013. Having established himself in the first team, Assombalonga became the club's top scorer that season with a total of 15 goals. Southend again extended Assombalonga's loan in December 2012, keeping him at the club until the end of the season. He played in the 2013 League Trophy Final against Crewe Alexandra which Southend lost 2–0.
