The Portuguese league leaders went ahead through Rodrigo on 29 minutes and extended their lead just before the hour mark from a Luisao header, before we hit back with a superb set-piece from Eriksen. But Luisao’s thumping strike seven minutes from the end left us with a real uphill task at the Estadio da Luz in seven days time.
There were three changes from the defeat at Chelsea at the weekend with Eriksen, Paulinho and Harry Kane drafted into the side, Michael Dawson, Gylfi Sigurdsson and Nabil Bentaleb making way.
And it was a cracking atmosphere in the build-up to kick-off as both sets of supporters cranked up the noise in anticipation of an eagerly-awaited cup tie. Unfortunately though, the game opened at quite a slow tempo with neither side making in-roads into the opposing defence.
A tame header goalwards by Luisao from Ruben Amorim’s free-kick on seven minutes was the first time either goalkeeper touched the ball, Hugo Lloris gathering comfortably, while Brazilian midfielder Sandro fired in our first shot across the bows, but it was wide of the target after good build-up play from Paulinho and Eriksen.
We enjoyed a spell of pressure midway through the half via a succession of corners, Benfica skipper Luisao twice in the right place at the right time to clear any danger before the opening goal to the visitors on 29 minutes.
A superb incisive pass from Ruben Amorim split Kyle Naughton and Jan Vertonghen to find Rodrigo running in from the right flank, he advanced into the area and curled his shot low past Lloris and in off the far post.
That proved to be the only shot on target in the half from either side and we went in trailing at the break.
Just four minutes into the second half we had a great chance to draw level as Eriksen led the break from midfield and slipped a pass in to Emmanuel Adebayor just inside the area on the right. With time to set himself and just the keeper to beat, the normally reliable striker dragged his effort wide of the far post.
And good work from Kane found Aaron Lennon out wide moments later, but his left-footed shot after cutting inside was easy for Jan Oblak at his near post.
Benfica went close to a second as the chances began to flow in the game, Kane losing possession 30 yards from goal and Ruben Amorim bringing a smart save from Lloris with a 25-yard drive. From the resulting corner, Luisao found himself unmarked on the edge of the six yard box and headed home to double the Portuguese side’s advantage, with 58 minutes on the clock.
We needed a spark urgently and Eriksen duly obliged. Six minutes later, Kane was upended 25 yards from goal by Silvio, the Benfica defender picking up a yellow card for the foul, and from the free-kick, the Danish ace delivered once again, curling a delicious shot up and over the wall past Oblak.
Younes Kaboul then brought a good save from Oblak with a far post header from Eriksen’s free-kick out wide on the left, while Lloris was almost caught out by Luisao’s long pass as he came to head clear but mis-judged the flight of the ball. Just as Rodrigo looked like he was going to win the race to the loose ball, the French keeper managed to dive in front of him and tip it away for a corner.
With seven minutes remaining though, the visitors restored their two-goal advantage. Substitute Nicolas Gaitan’s free-kick was met by Ezequiel Garay’s header, Lloris made a great stop low down to his left but the rebound fell to Luisao who smashed home off the crossbar from close range.
In the dying seconds, Benfica broke away again and almost compounded our misery with a fourth, but Lloris denied Guilherme Siqueira.
Spurs: Lloris, Walker (Rose 76), Kaboul, Vertonghen, Naughton, Lennon, Paulinho, Sandro (Bentaleb 82), Eriksen, Kane (Soldado 75), Adebayor. Substitutes (not used): Friedel, Fryers, Townsend, Chadli.
Benfica: Oblak, Silvio, Luisao, Garay, Siquiera, Ruben Amorim, Fejsa, Sulejmani (Perez 65), Markovic, Oscar Cardozo (Gaitan 65), Rodrigo (Lima 87). Substitutes (not used): Artur, Andre Almeida, Jardel, Djuricic.
Goals: Spurs – Eriksen 64; Benfica – Rodrigo 29, Luisao 57, 83.
Yellows: Spurs – Sandro, Vertonghen; Benfica – Silvio, Rodrigo.
Referee: Jonas Eriksson (Sweden).