Gaitan earns Benfica point at Porto
All four goals came from South Americans, a reflection of the growing influence in Portugal of players from that region.
There were 16 South Americans in the starting lineups and only three Portuguese.
Striker Kleber headed the opener for Porto on 37 minutes, rising above defender Maxi Pereira after a free-kick on the left from Colombian Fredy Guarin.
It was another boost for Kleber after he received his first Brazil call-up on Thursday.
The pace of the game picked up in the second half with two goals in quick succession.
Paraguay striker Oscar Cardozo levelled for Benfica when he slotted the ball past keeper Helton after good work from Spanish forward Nolito.
Champions Porto went back in front after 50 minutes as Argentine Nicolas Otamendi pounced on Varela's inviting pass.
Benfica snatched a point in the 83rd minute when Gaitan smashed the ball home following a perfect first-time pass from fellow countryman Javier Saviola.
On Tuesday, Benfica travel to Romania to play Champions League rivals Otelul Galati while Porto take on Zenit St Petersburg in the same competition on Wednesday.