Arsenal entered the tie at the Emirates trailing 2-1 on aggregate.
That changed quickly as Bendtner struck after 10 minutes thanks to an incisive through ball from Nasri to Arshavin, whose shot was deflected onto the willing Dane.
The little Russian himself was involved again 15 minutes later as he jinked for space and crossed to Bendtner again who tapped in for 2-0.
The game was give-and-take throughout the rest of the first half until Nasri invoked Zlatan for an absurd solo goal for 3-0. Arshavin released on a counterattack a minute afterwards to setup Eboue who finished calmly, 4-0.
Arsenal go through 5-0 on the day and 6-2 on aggregate after Bentner slotted a late penalty for his first hat-trick at a senior level.
Almunia (7) Though Porto found some success attacking, they put few shots on target. Almunia was tested on the few he received and almost got caught out after a clearance. Maybe he looked a little squirrelly but what goalkeeper doesn't, at times?
Sagna (6.5) One of the few Arsenal players not to play loudly. Got forward, got back; he was better than his opposite player without playing excellently himself.
Vermalaen (8) There is not a team in England that isn't jealous of the strong, intelligent defender Wenger signed a year ago January. The best defender in England this season continued a good vein in this European tie, generally owning his space.
Campbell (6) He's wily, but no longer quick or especially powerful.
Cliche (7) Despite looking funny, he played well enough to sustain the shutout, though Porto's wide attackers had moments of success. The French defender contributed predictably to Arsenal's flowing forward movements and will be chuffed enough by his individual performance and that of his team's.
Rosicky (6) From afar, perhaps still trying to enter a consistent run of form after debilitating injuries in past seasons. He shows flashes, but today dribbled better than he passed, with some error.
Song (7.5) Playing in front of defense, the Cameroonian has the skill and bottle desired and required. Solid game from a balanced player.
Diaby (7.5) Impresses with his attacking dribbling. The football seems to cling to his spidery legs. Tackles confidently also. Growing...
Arshavin (8) A tough rating, because he was inconsistent today. However, his positive moments were brilliant. He was casual at times passing in the midfield. But with the ball, one-on-one, he has few peers. The value of dribbling (if only seldomly) with opposite foot is perhaps the most underestimated in world football. Here, Arshavin's two-footedness, intelligence, vision, low base, and immense balance make him the classiest player currently plying on English shores.
Nasri (9.5) The nucleus for most of Arsenal's attack, Nasri prophesied his side's forward flow from the center, sans Fabregas. Dribbled with balance, but only after musing over various passing options first. His solo goal invoked memories of Zlatan's absurd goal for Ajax against NAC.
Bendtner (8) Not exactly the most graceful footballer from open play, but he is big enough to win headers and smart enough to go where the better players on his team are passing. Basically he had two easy goals today and got the hat-trick with the penalty. There are several more nuanced attackers on Arsenal, so perhaps this Dane's more straight-forward style aptly complements the team.
Eboue: Laughable? Perhaps. Effective? Certainly. Scored and drew a penalty.
Denilson: Shored things up.
Walcott: Brief cameo for mercurial winger/striker hybrid.
Helton (7) This guy had the kitchen sink thrown at him today. Under constant pressure, he had much to do. His defense was largely at blame for Arsenal's goals, though his chosen angle was poor for Arsenal's opener.
Bruno Alves (6) The player of the year in Portugal's domestic league didn't live up to the hype today. Arsenal, across the board, are better than Porto, and Alves' relationship to the players in red around him was microcosmic evidence.
Rolando (5) Honestly, he was invisible. Which is saying something, because his physique is salient, to say the least. When he fills out his awkward, sizable frame he may be quite a specimen as a footballer.
Pereira (5.5) Got forward well. Defended very poorly.
Fucile (5.5) Also got forward well. Also defended very poorly.
Meireles (5) Did enough to escape observation or particular scrutiny, which probably isn't enough for a game of this magnitude.
Hulk (6.5) Promising young attacker has immense strength, obviously. Wasn't able to showcase his powerful shot today. Should have tracked back more when his defenders were lamenting. Able to contribute to a Porto attack whose efficacy was not aptly portrayed by the five-nil line.
Cuelho (6.5) Left at half-time with his chin up, as the tie was still finely balanced. His side's defense suffered as a result of the attacking substitution.
Falcao (5.5) Had a few nice bursts forward, but, generally in good company at Porto as someone not up to snuff today. They were never going through.
Macael (6) Which player was he? Oh well. Porto were not muffled in the first half despite trailing. They enjoyed a good beginning to the second half until their brittle backbone cracked under pressure. Not too much blame going to the attackers, despite not scoring, if that's possible.
Varela (6) Another guy who may have been someone else. They were pretty much interchangeable. Flair, some runs to the byline, some crosses in, some shots here or there. Porto attacked better today than they defended.
Rodriguez: Completely unstoppable. Just kidding.
Guarin: Changed the game when he entered as Porto only had one sub left afterward.
Gonzalez: Didn't score or do anything to cause notice.