LISBON, Sep 30 (Reuters) Argentina striker Lisandro Lopez scored twice to give Porto a 2-0 home win over Boavista as they preserved their 100 percent league record.
Benfica and Sporting drew 0-0 in the Lisbon derby after both sides squandered several chances.
Porto's sixth successive league win -- their best start for 10 years -- gave them a boost before they travel to Besiktas in the Champions League on Wednesday.
The northern team lead the Premier League table with a maximum 18 points from six matches followed by surprise package Maritimo who have 12 points and a game in hand.
Sporting, who visit Dynamo Kiev in the Champions League on Tuesday, are third with 11 points and Benfica, who host Shakhtar Donetsk on Wednesday, are fourth eight points off the pace.
Porto went ahead after 15 minutes when Boavista goalkeeper Carlos parried a Ricardo Quaresma freekick and Lopez knocked in the rebound.
The Argentine wrapped up the three points with his second strike after 74 minutes from close range to become the league's top scorer with six goals.
The win restored Porto's confidence after they were knocked out of the League Cup by second division Fatima in midweek.
Reuters MP VP0450