The Portuguese side was down 1-0 on aggregate after the first leg but bounced back in Lisbon on Thursday to progress to the final at the Amsterdam ArenA later in May.
Nicolas Gaitan opened the scoring for the hosts in the early going before Dirk Kuyt levelled matters. Cardozo then took over scoring twice to secure the victory.
Benfica came out guns blazing and was rewarded for its attacking mindset when Gaitan unleashed a shot that bounced off the post and into the net in the ninth minute.
It was a dream start for the home side, but their ecstasy soon turned into agony when Fenerbahce won a penalty in the 23rd minute.
Kuyt stepped up to the spot and made no mistake to make it 1-1 on the night but 2-1 on aggregate for the Turkish outfit.
Benfica turned up the heat soon after looking for the go-ahead goal and came close on two occasions before Cardozo took center stage in the 35th minute.
The 29 year old beat his marker before turning smartly and finding the bottom corner. It was 2-1 for Benfica but it still needed another goal to progress due to Fener’s away goal.
The tie was still very much up for grabs as the teams headed into the half-time break.
Benfica came out the more ambitious side as one would expect but could not find a way through Fenerbahce’s wall of defenders. The visitors had 10 men behind the ball and the Portuguese club could not find any openings.
However, that changed in the 66th minute when Cardozo was first to the ball and fired home into the bottom corner. The hosts now had the lead on the evening and on aggregate.
Fener pushed forward looking for the goal that would put it in the final but could not pierce Benfica’s backline.
Oscar Cardozo was the hero as his two goals propelled Benfica into the Europa League final where it will meet Chelsea in Amsterdam.