Atletico Madrid missed out on taking the leadership after drawing 1-1 at Deportivo La Coruna.
With fellow pacesetters Real Madrid and Barcelona not playing until Saturday, Atletico were on course to move one point clear at the summit following Tiago's first-half strike.
But Lucas took advantage of some poor defending from Jose Maria Gimenez to net the equaliser in the 76th minute and deny the visitors, who remain third, a fourth consecutive win.
Former Chelsea and Portugal midfielder Tiago broke the deadlock in the 33rd minute when Deportivo failed to clear their lines and his half-volley from the edge of the box flew into the bottom right-hand corner.