The referee pointed immediately to the spot and Dybala dispatched the ensuing penalty kick to give Juventus a decisive 1-0 advantage after already holding a 2-0 aggregate lead from the first leg in Porto.
He said: 'It would be insane to win the Champions League at my age because I only joined Juventus two years ago.
"There are other great teams in the tournament, but we have quality and we've got what it takes to win the trophy".
Nevertheless, Dani Alves - who defeated Juve in the 2014-15 Champions League final during his time at Barcelona - is confident the Bianconeri have what it takes to go one better this term.
'We're also top of the league and we won the first match of the Coppa Italia semi-final.
Twice Juventus had opportunities to make the breakthrough in the opening three minutes, but Higuain headed wide of the post from outside the Porto box, before Dybala fired over the crossbar from close range after breaking through.
In the Champions League, they've won eight of 13 unbeaten home games since 2014/15, though they have drawn four of the last six of these.
Higuian nearly put the game to bed in the 67th minute, the Argentinian striker turned away from his man in the box but he dragged his shot just wide.
"Whoever qualifies for the next round can become a contender for the Champions League".
Juve striker Gonzalo Higuain has scored only two goals in 21 Champions League knockout games.
Porto substitute Diogo Jota had a chance to salvage some pride when he went through on goal in the closing stages, but he over hit his chip and the chance went begging along with Porto's European campaign for another year.