Sergio Martínez Mantecón (born 8 June 1980) is a Spanish former professional footballer who played as a defensive midfielder. He is the current technical secretary of Elche CF.
The following two years, Mantecón was a regular starter for the Extremaduran side, being relegated in 2003. In August of that year he signed with Alicante CF of Segunda División B,[2] going on to appear twice in the promotion playoffs but falling consecutively short.
On 29 June 2006, Mantecón moved to Hércules CF in the second division.[3] After being regularly used in his first season he was left out of the squad in his second, and subsequently joined third-tier SD Ponferradina in January 2008.[4]
Mantecón agreed to a two-year contract with CD Castellón on 24 June 2008.[5] After experiencing another relegation in 2010, he joined fellow league club Elche CF in the off-season.[6] He started in 25 of his 39 matches in 2012–13 as they returned to La Liga after more than two decades, then signed a new one-year deal.[7]
On 19 August 2013, the 33-year-old Mantecón made his debut in the Spanish top flight, replacing David Generelo midway through the second half of a 3–0 away defeat to Rayo Vallecano.[8] After only 12 appearances and two starts during the season, he was released in June 2014[9] and moved to Cádiz CF of division three.[10]
In February 2017, Mantecón signed with Tercera División club CF Lorca Deportiva,[11] and retired shortly after. In July, he returned to Elche as part of the technical staff.[12]