Benfica failed to make the most of an opportunity to pull clear as they were held to a goalless draw by Sporting Lisbon.

It is only the third game this season Benfica have dropped points and they will be overtaken at the summit on Monday if Braga beat Uniao Leiria.

Just one point separates the top two sides in the standings.

In tonight's other match, Nacional needed a last-minute goal to snatch a 1-1 draw at home at Naval.

Mario Camora's strike at the end of the first half looked to have won the game for the visitors until substitute Mateus da Costa popped up to score in the dying seconds.

Nacional remain fourth in the table, six places and seven points better off than their opponents.