 Born in Dourados, Mato Grosso do Sul, Lucas began his career at Grêmio as a midfielder in 2005.The following year was a successful year for him, as Grêmio won the Rio Grande do Sul state championship (the Campeonato Gaúcho) for the first time since 2001, and also came third in the Campeonato Brasileiro Série A. Lucas also became the youngest player ever to receive "Placar" magazine's "Bola de Ouro" (Golden Ball), given to the best player in the Campeonato Brasileiro – an honour previously won by the likes of Zico, Falcão, Careca, Alex, Romário, Robinho, Kaká and Carlos Tevez.His form in 2006 led to reported interest from many major European clubs including offers from top Spanish clubs and Internazionale.