Gundogan toasts last-gasp 'liberation' as Euro hosts Germany top group
Germany were a goal down after Dan Ndoye's 28th-minute opener, which had allowed the Swiss to leapfrog the home side into top spot in Group A.
With two minutes of stoppage time played, Fuellkrug headed in a perfect cross from David Raum to level the scores and save top spot for Germany.
The result means Switzerland, rather than Germany, face a tougher last 16 assignment, setting up a potential meeting with holders Italy or 2018 World Cup finalists Croatia.
"That can liberate us - and the fans," the Barcelona midfielder told Germany's ARD network.
"We were unfortunately behind and then wanted to equalise to win the group. We can benefit from having managed to achieved this in the next games.
"Of course we would have liked to win 3-0. But I think that you also need games like that. It can give you a boost. That was very, very good for morale."
The goalscorer Fuellkrug praised coach Julian Nagelsmann's substitutions and said the goal could be "decisive" for the hosts.
With Germany chasing the game, Nagelsmann brought on both Fuellkrug and Raum, who combined for the equaliser.
"It wasn't just me - all the substitutes worked well. The cross was perfect. That was a nice moment for us as a team, that could be decisive.
"That changes the situation. Now we're facing the supposedly easier opponent, let's see who it will be."
Nagelsmann himself said: "The equaliser was deserved, as was the group victory. We threw everything forward at the end."