Benfica and Sporting draw
Lisbon rivals Benfica and Sporting drew 1-1 in game both clubs needed to win to close in on leaders Porto who lost 2-1 at Boavista.
With three matches left, Porto are top with 62 points, three ahead of Sporting and four of third-placed Benfica.
Sporting, unbeaten away from home, took the lead after just two minutes when Brazilian striker Liedson headed in a perfect right wing cross by Abel.
Cheered on by a crowd of more than 50,000 at the Luz stadium, Benfica equalised after 24 minutes through Italian winger Fabrizio Miccoli after Sporting's keeper Ricardo had parried a shot.
The derby was marred by skirmishes involving Benfica fans and police outside the stadium before the kickoff. Two police were slightly injured.