Универсидад де Чили
Born in Santiago, Tello began his career at local Club Universidad de Chile, making his professional debuts in 1999. He quickly made a good impression, being named the best midfielder in the country in 2000 and being transferred to Sporting Clube de Portugal for a fee of €7 million in January of the following year, alongside compatriot Mario Cáceres; at the time, it was a club record for the Primeira Liga side.