Sergio Martínez Ballesteros is a Spanish professional footballer who plays for Levante UD in La Liga, as a central defender. Born in Burjassot, Horta Nord, Valencian Community, Ballesteros came through the ranks of local Levante UD. In January 1996 he moved on loan to the Canary Islands' CD Tenerife, making his La Liga debut on 3 January in a 2–0 home win against Racing de Santander. In 2000–01 Ballesteros moved to Madrid's Rayo Vallecano, collecting 10 yellow cards during his only season and playing all the games and minutes in the club's quarterfinal run in the UEFA Cup. He subsequently spent three years at Villarreal CF. From 2004-08 Ballesteros represented RCD Mallorca in the top flight, receiving six additional marching orders in over 100 first-team appearances. He rehoined Levante after thirteen years. Veteran Ballesteros rarely missed a match for the Granotas in the following seasons, making 34 appearances in 2010–11. He fared even better the following campaign – also finding the net once, at Rayo Vallecano in a 2–1 success.