Boavista FC secured three points thanks to Cafu's deciding goal against Varzim SC 2-1 on Tuesday.
Cafu struck 15 minutes from time, heading in an Elpídio Silva cross, to illuminate an otherwise uneventful second half. Varzim had been on course to take a point from Porto when Rodolfo netted after goalkeeper Ricardo failed to hold Toni Vidigal's centre on the stroke of half-time.
Boavista had gone ahead through Erwin Sánchez's free-kick which slipped under visiting keeper Fernando Pontiroli. The win lifted Boavista into seventh place on the day they were drawn to face Cypriot team Anorthosis Famagusta FC in the UEFA Cup second round.