The Wolfsburg winner linked up with fellow substitute Kamil Grosicki to give his team hope in the pulsating League of Nations encounter.
The Hull winger ran down the right, with the ball appearing like it may have gone out of play, but appeals were waved away.
Grosicki delivered into the box and although Robert Lewandowksi could not control on the occasion of the 100th cap the ball fell to the other former Dortmund man.
He unleashed a stunning volley past Rui Patricio to cut Portugal's lead in the match.