Lisbon - Basel advanced to the Champions League knockout rounds by beating Benfica 2-0 with another perfect start in their last group game on Tuesday.
Norwegian forward Mohamed Elyounoussi gave the home side the lead with a headed effort from a cross from Michael Lang five minutes into the match.
The Swiss champions finished second in Group A, three points behind Manchester United, who came from behind to beat CSKA Moscow 2-1 at Old Trafford.
"We've come a long way, the progress in the last two to three months has been good," Basel coach Raphael Wicky said. "Twelve points is unbelievable."
Moscow were a further three points behind Basel and booked a spot in the Europa League.
Benfica completed a poor campaign without a single point while scoring only a single goal.
"We weren't inferior to Basel but mistakes are costly," Benfica coach Rui Vitoria said. "We always want things to run well, but this season we are in a negative mood. We had a run of situations that weren't normal in the Champions League. We didn't win and we are sad for it."
The Portuguese side didn't look resigned despite resting several regular starters, and pressed for an equaliser. But it was the visitors who created better scoring chances on quick counters.
In the second half, forward Dimitri Oberlin doubled the lead by netting a header from close range to send the Swiss side to the knockout phase for the first time since the 2014-15 season.