Mohamed Elyounoussi and Dimitri Oberlin scored headers to send Basel into the knockout phase of the Champions League, earning a 2-0 win at already-eliminated Benfica on Tuesday.
Basel knew victory at a half-empty Estadio da Luz would almost certainly be enough to qualify from Group A, barring an unlikely heavy win for CSKA Moscow away to Manchester United.
Although CSKA did take the lead at Old Trafford, the Premier League side came from behind to win - Basel qualifying in second place behind United after winning four of their last five games in the competition.
Elyounoussi headed Basel into an early lead with his first goal in the Champions League proper, the forward left all alone in the penalty area to convert a terrific cross from Michael Lang, who had scored a dramatic late winner at home to United on matchday five.
But thereafter the game was largely dominated by Benfica, Lisandro Lopez twice going close while a Haris Seferovic drive forced a fine save from Basel goalkeeper Tomas Vaclik.
Basel's resilience protected their clean sheet and when Manuel Akanji got up highest to flick on Luca Zuffi's free-kick, Oberlin was in position to nod home and secure the crucial victory for his side.
FULL TIME! | @slbenfica_en 0-2 FCB
BASEL QUALIFY FOR THE ROUND OF 16 OF THE @ChampionsLeague! #SLBFCB #FCBasel1893 #UCL #zämmestark pic.twitter.com/5NA8DlLzPS — FC Basel 1893 EN (@FC_Basel_en) December 5, 2017
The Swiss champions thrashed Benfica 5-0 at home earlier in the group, Lang on target early in that win, and they took just five minutes to open the scoring in Lisbon.
Marek Suchy found Lang in plenty of space on the right, the wing-back delivering a sublime cross that Elyounoussi flicked beyond teenage goalkeeper Mile Svilar.
Pizzi sliced an ambitious strike wide before a Lisandro effort was deflected off target by goalscorer Elyounoussi as Benfica sought to salvage some pride.
The hosts continued to dominate despite trailing and Vaclik had to make a smart save away to his right to keep out a drive from Seferovic.
But Basel should have settled the game on the break after 37 minutes, Renato Steffen trying and failing to play in Oberlin when he had a clear sight of goal himself.
Eliseu headed Andrija Zivkovic's corner straight at Vaclik as Benfica ended the half on top.
Basel had won their last five games in all competitions and evidently felt a one-goal lead would suffice, the visitors continuing to sit back after the restart.
A Lisandro header from a Pizzi corner looped narrowly wide and the arrival of Jonas from the bench added a much-needed goal threat for the hosts.
But Basel extended their lead after 65 minutes by profiting on yet more sloppy Benfica defending in the air.
Oberlin scored twice against Benfica earlier in the group and he stooped to convert after Zuffi's free-kick was headed on by Akanji.
The in-form Lang went close to adding gloss to the scoreline, but Basel were content to see the game out, leaving Benfica without a goal in five successive Champions League matches.