Club Friendlies Wrap: Varela inspires comeback win for Porto
Deportivo went ahead through Edwin Aguilar in the 38th minute before the highly rated Jackson Martinez responded for Porto with a header at the back post early in the second half.
Juan Fuenmayor surprisingly restored the Venezuelans' lead on the hour-mark before Eliaquim Mangala equalised.
Varela's powerful header finally put Porto ahead in the 65th minute and he sealed the result in the dying moments with a neat finish from a tricky angle.
AZ Alkmaar were convincing winners in their friendly against La Liga side Getafe, claiming a comfortable 3-0 victory.
Roy Beerens tapped in a Johann Gudmundsson cross just 16 seconds in and Rasmus Elm made it 2-0 in the 14th minute.
Getafe midfielder Michel was sent off early in the second half and Aron Johannsson added a third for AZ.
In other matches, Mallorca overcame Lokeren 1-0, Bordeaux got past Mechelen 2-1 and Kortrijk and Club Brugge played out a 2-2 draw.