Ahead of kick-off, only Liverpool had netted more Europa League goals than Marseille's tally of 24 this season, but Les Phoceens found clear-cut chances difficult to come by tonight in Lisbon and have it all to do when they play host to the reigning Primeira Liga champions next week.
It was the Eagles that began the match the brighter of the two sides, and they almost took the lead inside the first six minutes when they were presented with a huge opportunity from a cross off a short corner that found Alexander Bah in the box. However, despite stealing a march on his marker, the Benfica right-back was unable to connect properly with his effort from close range, and Marseille were able to clear their lines.
The visitors began to find their stride leading up to the 15-minute mark, but moments after managing their first foray into the opposition's box, they were carved apart by a sweeping attack from David Neres and Casper Tengstedt, with the latter slipping a neat pass into the path of Rafa, who prod home the opening goal of the evening.
Benfica were dictating play for the next 10 minutes and nearly went two up midway through the half when Rafa turned provider for Tengstedt with a pin-point pass, but Leonardo Balerdi intervened with a superb, well-timed tackle, denying the Dane a shot at goal and keeping the deficit at just one.
The home fans would undoubtedly have been happier in the first period as they watched their side limit the Ligue 1 outfit to little in the way of goalscoring chances, managing just three shots at goal, though none of them were on target.
With the interval approaching, Marseille were dealt an injury blow, with Quentin Merlin going down under a challenge by Neres, which caused his leg to buckle beneath him and led to him being taken off on a stretcher in notable pain. Gasset brought on Iliman Ndiaye to replace the stricken Merlin in first-half stoppage time.
Di Maria, who had scored 15 goals and provided 13 assists in all competitions, including six goals in his last five appearances in European competition ahead of this one, was the standout player for the hosts in the opening minutes of the second period and added to his tally after exchanging a quick one-two with Neres, whose cutback for the goal was laid on a plate for the Argentine to finish.
Roger Schmidt's side continued to boss the game leading up to the hour mark, but a momentary lapse of concentration in defence almost saw their deficit halved, as Ndiaye made his way into the box and fired a snapshot towards the near post which crept just wide.
However, that near miss seemed to spark the visitors into life, and Ndiaye was once again at the heart of the action, slotting a through-ball to Aubameyang in the box moments later. The current top-scorer in this competition made no mistake, netting his 24th goal of the campaign and 10th in this season's Europa League with a composed side-foot finish beyond a helpless Anatoliy Trubin.
After a brief loss of composure following their concession, Benfica regained their rhythm in the final 10 ten minutes of regulation time but were evidently cautious in their approach, opting against throwing too many bodies forward in search of reestablishing their two-goal cushion.
The Eagles were content holding on to possession late on and shut up shop in the final moments of the match to secure their advantage in the tie ahead of what promises to be another absorbing encounter in Marseille next week.