Atletico Madrid secured top spot in Group C of the Champions League as goals from Saul Niguez and Luciano Vietto earned a 2-1 win at Benfica on Tuesday.
The hosts only needed a draw to top the standings but Atletico's win saw them claim their place at the summit at the expense of the Portuguese side.
Saul celebrated his return to Diego Simeone's European starting XI with a first-half strike, while Vietto added a second after the break as Atleti recorded their seventh successive win in all competitions, avenging their 2-1 defeat to Benfica at the Vicente Calderon in September in the process.
Konstantinos Mitroglou came off the bench to give the home side hope with 15 minutes remaining, but Atletico held on.
Benfica could now face one of Real Madrid, Bayern Munich or Barcelona in the last 16 when the draw is made on Monday.
Atletico, meanwhile, will take on one of the group runners-up and will enjoy home advantage in the second leg.
Despite Benfica knowing that a point would be enough to secure top spot, the hosts were happy to allow an open and expansive match, which took quarter of an hour to come to life.
Diego Godin had the ball in the back of the net in the 18th minute but the defender's header was ruled out for offside, while Atletico tested home goalkeeper Julio Cesar three minutes later, as Saul's long-range effort forced a good save from the Brazilian.
Cesar was in action again in the 22nd minute, palming away Gabi's powerful attempt from the edge of the box, but the keeper could do nothing to prevent the visitors taking the lead just after the half-hour mark.
Antoine Griezmann's tidy throughball picked out the run of Vietto, who unselfishly centred for Saul to sidefoot home his third goal of the season from 12 yards.
It took Benfica 38 minutes to muster a shot on goal, with Goncalo Guedes dragging wide from 18 yards, but the hosts came out with intent after half-time.
Atletico soon regained their stranglehold on the game, however, and Vietto doubled their advantage in the 55th minute.
Yannick Ferreira Carrasco stole a yard on his marker down the left and crossed low to the near post, where Vietto prodded beyond Cesar for his first Champions League goal.
Just as their chances of finishing above their guests appeared to be dwindling, however, Mitroglou gave Benfica fresh hope. The Greek turned Godin in the box and beat Jan Oblak, with the ball finding the net off the inside of the post.
Benfica pushed hard for an equaliser in the final 10 minutes, with Eliseu seeing a low shot saved by Oblak, but Atletico held out to end the night top of the group.