Nacional and Boavista have played out a goalless draw in the Primeira Liga in a match where both sides were reduced to 10 men.
The visitors came into the fixture looking to avenge their two defeats in the league last season, where Nacional claimed 2-1 and 1-0 victories.
However, neither side were able to break the deadlock in the first half as they struggled for quality in the final third of the pitch, with Paulo Vinicius coming closest for the visitors when he headed over the bar from a corner.
In the second half, Boavista threatened when Luisinho raided at goal and curled an effort towards the bottom corner, but Rui Silva palmed the ball past the post.
The visitors were reduced to 10 men when Renato Santos was sent off for his second booking, just two minutes after picking up his first caution.
Nacional could not take advantage as Jota was dismissed for a challenge on Tiago Mesquita in the 78th minute.
The home side had the chance to win the game in the dying minutes when Zainadine headed at goal, only to see his effort crash off the crossbar and bounce to safety.
The result leaves Boavista in 10th place in the Primeira Liga and Nacional sit in 12th.
