Goals in either half from Jonas have helped Benfica beat Pacos de Ferreira to close the gap on leaders Porto.
The Eagles almost found a breakthrough midway through the first half after Nicolas Gaitan's cross fell into the path of Goncalo Guedes, but the Pacos defence were able to clear away the danger.
However, the Lisbon outfit took the lead on 34 minutes when Jonas's spectacular strike left keeper Marafona beaten.
The Brazilian frontman almost scored a second within moments with another well-taken shot, but his effort drifted wide of the post.
Benfica doubled their lead on 67 minutes as the youngster Guedes netted for the hosts.
Six minutes later, the home side wrapped up victory after Gaitan's menacing delivery found Jonas and the forward tucked his effort beyond the reach of Marafona.
Chris O'Keefe
