Poor marking from Silva, however, allowed Martinez to sneak in behind at the back post and head in right back Danilo's cross from the right.
PSG combined spells of electric attacking moves with periods of disjointed play and a lack of ideas. Porto's seamless passing and movement, allied to athletic running down the flanks, gave the Portuguese side a more cohesive look.
"A few times we had problems when we defended too deep (in the first half), so I told the players to close down higher up the pitch," Ancelotti said.
Porto goalkeeper Helton's agility kept the scores level at the break. Ibrahimovic almost lobbed him with an instinctive snap header after latching onto Silva's headed flick on in the penalty area.
PSG should have gone ahead early in the second half when Alex's pass released Menez down the left, but he took too long to line up his shot and that allowed Danilo time to close him down.
Menez's fine dribbling ability goes in tandem with his wasteful finishing, and he confirmed his reputation as an inconsistent scorer when he blasted the ball straight at Helton after Javier Pastore had played him in perfectly.
PSG then went ahead following a quickly worked corner. Menez passed to Lavezzi, and Helton allowed his low shot to squeeze past him and into the bottom corner.
"We have to react well to this match," Porto midfielder Joao Moutinho said. "We created chances but we could not win. "
Porto missed a great chance to equalize when Martinez found space inside the penalty area, only to be denied by a point-blank save from goalkeeper Salvatore Sirigu in the 79th. The rebound fell to Lucho Gonzalez, who blazed the ball high over the crossbar with the goal at his mercy, prompting howls of derision from the crowd at Parc des Princes.
Ibrahimovic, who had a quiet match, was jeered by the home fans for trying an extravagant shot from 25 meters, rather than pass the ball to an unmarked Menez.
To make matters worse, the imposing Swede then shot wide from six yards. Pastore, having his best game of a troubled season in which he has been in and out of the team, went close with a glancing header in the 88th.
"(Pastore) worked for the team, he defended, he had a fine game," Ancelotti said.