Benfica's slim hopes of holding on to their Portuguese league crown were all but crushed after they conceded a late goal and were held to a 1-1 draw at Famalicao on Thursday.
It left the Lisbon giants eight points adrift of leaders Porto, who won 3-1 at Tondela, with three games left.
Porto, who sit on 76 points, need only a point to guarantee taking the title from Benfica, who can reach a maximum of 77 if they win their remaining games.
As Porto beat Benfica home and away this season, they have the advantage of a better head-to-head record between the clubs, which is used by the Portuguese league as the first tie-breaking criteria if teams finish with the same number of points.
Benfica took the lead through Pizzi's simple tap-in after 37 minutes, with Haris Seferovic's initial effort having been saved by goalkeeper Rafael Defendi.
But substitute Goncalo Rodrigues equalised in the 84th minute to earn a share of the spoils in a lively match in which Fabio Martins also rattled the Benfica bar in the second half.
The point kept up Famalicao's hopes of clinching a Europa League place next season despite having only just been promoted to the top flight. They remain in sixth place on 49 points, four points off the European places.
Benfica next host seventh-placed Vitoria Guimaraes on Tuesday and if they fail to win they will hand the title to Porto, who play on Wednesday at home to Sporting.
