Benfica defender Maxi Pereira scored the winning goal
It was a tale of two halves as Zenit St. Petersburg traveled to Benfica hoping to protect the 3-2 advantage they'd gained in the first leg of their Champions League tie.
For the first five minutes, Zenit looked like they would take a cautiously adventurous approach to the match.
A couple of Benfica chances later and they seemed to collectively change their minds.
For the rest of the first half, the Russians bunkered in without any attacking intent—even on the counter.
Benfica take control
As a result, Benfica pushed wave after wave of attacker forward.
Maxi Pereira spent the entire half firmly ensconced in and around Zenit's penalty area, despite being deployed as Benfica's right back.
Maxi combined with midfielders Bruno Cesar and Axel Witsel throughout the first half, creating chance after chance.
Despite the pressure, Zenit held out until the first minute of extra time. That's when Benfica's right-side trio combined to change the balance.
Witsel drove at the Zenit backline, played a one-two with Bruno Cesar inside the box, and got a shot away from six yards.
Zenit goalkeeper Vyacheslav Malafeev made the initial save, only to see the rebound fall straight back to Witsel.
The Belgian midfielder's backheel found a charging Maxi, who got the goal his work down the right side so richly deserved.
Zenit try to change gears
Finding themselves trailing on the away goals rule, Zenit gamely attempted to change their approach in the second half.
They immediately pressed Benfica higher on the field and pushed additional players forward while in possession.
How far can Benfica advance in the Champions League?
In contrast, Benfica dropped further into their own half and seemed happy to hold what their first-half goal had won.
Nothing showed the change in spirit more than the fact that right back Maxi stayed firmly put in his defensive zone for the entirety of the second half.
There was one big difference between Benfica's approach to the second half and the way Zenit had played the first: Benfica married their conservative set-up with a dedication to quick counterattacking at every opportunity.
So Zenit looked to chase the game, but found themselves lulled into possession for possession's sake.
Despite having more than 60 percent of the ball in the second half, Zenit only managed to put two shots on goal.
Having taken the field intending to defend, they simply could not shift into a more dangerous attacking mode.
Benfica's counter pays off
While the Portuguese sat back in the second half, lively players like Witsel, Bruno Cesar, and Nico Gaitan continued to be dangerous on every counter.
The blunt edge for Benfica's attack all match long was the uninspired play of forward Oscar Cardozo.
He was eventually replaced by 20-year-old Nelson Miguel Castro Oliveira late in the proceedings. The difference was immediately apparent.
Oliveira's energy paid off in the third minute of extra time, when Bruno Cesar rewarded the striker's lung busting run by playing him in on the last movement of the game.
Oliveira hit it first time and found himself celebrating his first Champions League goal, as well as his team's progress to the quarterfinals.
Benfica won 2-0, and the tie 4-3 on aggregate.