Porto go top after late Madeira drama
Brazilian midfielder Edson Sitta put Nacional in front with a deflected shot after 14 minutes but Porto equalised through Brazilian striker Hulk after goalkeeper Bracalli parried a Lisandro Lopez shot on 51 minutes.
Uruguayan winger Cristian Rodriguez put Porto ahead for the first time with a volley on 72 minutes, but the home side levelled through Miguel Fidalgo six minutes later.
The champions clinched the three points when Argentine Lucho Gonzalez scored from the penalty spot in stoppage time and two minutes later Hulk confirmed the victory with his second goal.
Porto went top after promoted Trofense ended Benfica's unbeaten start to the season with a 2-0 home win.
Striker Reguila, taking advantage of a blunder by Benfica keeper Moreira, put Trofense ahead a minute from the break
Benfica were reduced to 10 men in the 64th minute when Cameroon midfielder Binya was sent-off for two bookable offences and conceded the second goal eight minutes from the end when Helder Barbosa tapped home a cross from the right from substitute Pinheiro.
Porto lead the standings with 27 points from 13 matches, followed by Benfica and Sporting, who beat Vitoria Setubal 2-0 on Saturday, both on 26.