Rafa broke open a scoreless match at the Jamor on Saturday night with a goal in the 59th minute, thanks to a defensive miscue, and Pizzi finished off the three points with a goal in stoppage time to keep the Eagles undefeated in Liga NOS play with a 2-0 win.
Belenenses featured five players in the back line, but it was not enough to avoid defeat after Rafa fired home the goal from the top of the box.
Belenenses manager Silas was disappointed not to score with their three opportunities, but praised his team for their effort against the defending league champions.
The win gave Benfica manager Bruno Lage his first career win against Belenenses.
Meanwhile, up north on Saturday, FC Porto ended a two-match winless streak, which included a devastating home loss to Krasnodar on Wednesday that eliminated them from the lucrative Champions League.
Ze Luis notched a hat-trick and Luiz Diaz scored the fourth goal for a 4-0 home win in front of 38,820 at Estádio do Dragão.
The win helps take the pressure off manager Sérgio Conceição.
“I have to give the players a word after a difficult week for FC Porto,” said Conceição. “We are not used to going down, especially after last loss, which cost us our presence in the Champions League. There was this difficulty for the match, it was more emotional. Everyone is to be congratulated.”
Next Saturday (19:00, BTV), the first Classico of the season takes place with FC Porto traveling to Lisbon to play Benfica in an expected sold out Luz.