Late Maicon header ensures Porto beat Benfica
Porto's triumph in the 'Classico' gave them 52 points from 21 league matches, three clear of second-placed Benfica.
The visitors started confidently and scored after seven minutes through burly Brazilian Hulk who surprised goalkeeper Artur with a venemous left-foot shot from outside the box.
Benfica had a chance to equalise after 23 minutes but Paraguay striker Oscar Cardozo's shot was easily saved by Helton.
Cardozo eventually struck five minutes before half-time after finding himself unmarked in the area and the same player made it 2-1 early in the second period when he nodded in a Pablo Aimar free-kick.
Porto coach Vitor Pereira then took a gamble, taking off centre-back Rolando and bringing on Colombia winger James Rodriguez, and the move paid off.
Rodriguez, 20, ran half the length of the pitch, exchanged passes with Brazilian midfielder Fernando and left-footed the ball into the net after 65 minutes.
Benfica left-back Emerson was sent off 12 minutes later and Porto took advantage of the extra man when Maicon towered above the defence to nosd the winner.