Rodrigo Mora (number 10) gave Portugal the lead
Scotland sustained successive defeats in European Under-21 Championship qualifying as Portugal triumphed at Fir Park.
Geovany Quenda crossed for Rodrigo Mora to head the visitors in front in the 20th minute.
After the break, the hosts gave up possession in their own half and Mora teed up Roger Fernandes to lash home the second and clinching goal.
Portugal, who had Mateus sent off on 72 minutes for a second booking, join Czech Republic on six points after the first two rounds of games. Bulgaria have four points.
Scot Gemmill's Scots, who lost away to the Czechs on Friday, face Gibraltar (home) and Azerbaijan (away) next month, with Gibraltar also yet to register a point and Azerbaijan sitting on one point.
