Bernard Mensah was on target as Vitoria Guimaraes and Nacional shared the spoils in Primeira Liga on Monday.
Manuel Machado's side was defeated by high-flying Sporting last week but Nacional - 10th in the standings - bounced back at Estadio da Madeira.
Matias gave Nacional a dream start after putting the ball in the back of the net barely a minute into the contest.
It was all Guimaraes, which cemented a spot in next season's UEFA Europa League via the third qualifying round, from that point on the back of two goals before half-time.
Valente equalised in the 14th minute and Bernard Mensah put the visitor ahead eight minutes before the interval.
But Nacional regrouped to earn a share of the spoils thanks to Matias, who levelled proceedings 13 minutes from time.