Benfica keeper Marcelo Moretto turned in a man-of-the-match performance as his side held favourites Barcelona in their quarter-final first-leg.
Eto'o and Ronaldinho were both frustrated by the Benfica keeper
Moretto made a catalogue of superb stops to frustrate Barca, twice saving from Ronaldinho in the opening minutes.
In the second half Barca hit the post twice, Moretto pushing Henrik Larsson's shot onto the woodwork, with Thiago Motta then heading against the upright.
Substitute Fabrizio Miccoli went close for Benfica after a run and a shot.
At times, given the fluidity and ambition of their attacking play, Barcelona gave the impression of being the home team.
Invariably Ronaldinho was the originator of much of the visitors' beguiling play, prompting his team-mates with his vision and bewitching Benfica with his ball skills in equal measure.
But Barcelona were unable to take a goalscoring lead back to the Nou Camp for next week's second leg, and that had much to do with Moretto.
The Benfica goalkeeper's best save came in the second half when he flung himself to his left to touch away Mark Van Bommel's precise shot.
Moretto had been quickly into action after Cleber Beraldo Anderson gave away a free-kick in his own box after referee Steve Bennett adjudged the Benfica defender's backpass had been intentional.
Moretto partially saved Ronaldinho's free-kick and when the ball rebounded to the Brazilian his waspish volley was athletically tipped over by the Benfica keeper.
Just before the interval a second Anderson error presented a golden opportunity for Samuel Eto'o, who was denied by Moretto from close range.
Not that Moretto was immune from making the occasional error, his weak backpass going to straight to Van Bommel, who proved unable to capitalise, steering his shot wide of the post.
Earlier Van Bommel had zig-zagged his way into the Benfica box, only for Moretto to clear the Dutchman's shot with his feet.
Sloppy finishing also played a part in Barcelona's inability to find a way past Moretto.
Most culpable was Deco, who casually sidefooted wide after Eto'o had cut the ball back for the Portuguese midfielder with only Moretto to beat.
In between those chances, Benfica were restricted to shots outside the box, with Sabrosa Simao, Manuel Fernandes, Geovanni and Petit all trying their luck in the first half.
In the opening stages of the second period, Moretto and the Benfica goal continued to live a charmed life, notably when Barcelona hit the woodwork twice in the space of a minute.
The home side finally managed to force their way into the Barcelona box thanks to Fabrizio Miccoli, whose shot was pushed away by Victor Valdes, with Geovanni unable to convert the rebound.
On 79 minutes Petit threaded the ball through to Simao, who was unable to beat Valdes.
Benfica coach Ronald Koeman:
"The result of this game gives us a chance.
"Barcelona have to attack more, playing in front of their fans, but if we were to play like we did in the second half we have a chance.
"If we go in like we did in the first half, we'll have a lot of problems."
Barcelona coach Frank Rijkaard:
"It was a shame we couldn't score, but the team worked hard and played quite well.
"In the next game we're sure to score. Normally a draw away from home is a good result."
Benfica: Moretto, Ricardo Rocha, Luisao, Anderson, Leo, Beto, Petit, Manuel, Simao, Robert (Miccoli 45), Geovanni (Karagounis 68).
Subs Not Used: Quim, Mantorras, Karyaka, Marcel, Nelson.
Barcelona: Valdes, Belletti, Oleguer, Motta, Van Bronckhorst, Deco (Gabri 76), Van Bommel, Iniesta, Larsson (Giuly 76), Ronaldinho, Eto'o.
Subs Not Used: Jorquera, Maxi Lopez, Ezquerro, Sylvinho, Rodri.
Booked: Iniesta, Deco, Belletti.
Ref: Stephen Bennett (England).