Schalke clinched the last Champions League place in Germany by beating Freiburg 2-1 in the final round of the Bundesliga on Saturday.
Schalke's shot from American Jermaine Jones was not on target, but Immanuel Hohn got caught in two minds and his attempted clearance hit his own teammate, Schuster, to cannon in for Schalke's second.
"Such a showdown, it was pure drama and excitement. I'm exhausted but very happy that we've reached our aim," said Schalke coach Jens Keller, who could have been talking about the day's action.
Freiburg will return to the Europa League for the first time in over a decade.
Also Saturday, Fortuna Dusseldorf was relegated while Hoffenheim escaped automatic demotion by winning 2-1 at Borussia Dortmund -- although that was only after Dortmund striker Robert Lewandowski's injury-time goal was ruled out for offside.
Lewandowski made it 1-0 in the sixth minute. But Sejad Salihovic equalized from the penalty spot in the 77th, and scored another spot kick five minutes later after Dortmund goalkeeper Roman Weidenfeller was sent off.
Dortmund now has injury worries over Mats Hummels, who limped off after conceding the first penalty and is a doubt for next Saturday's Champions League final against Bayern at Wembley.
"His ankle is swollen. That's not good. It will be close for Saturday," Dortmund coach Juergen Klopp said. "Now we're drawing a big thick line through the Bundesliga season and want to make sure all our players are fit for the final."
Hoffenheim, which features Americans Fabian Johnson and Danny Williams on its roster, now faces Kaiserslautern, which finished third in the second tier, in a two-legged play-off for the right to stay in the Bundesliga.
"The end was very emotional. We're happy now that we still have the chance to stay in the league," said Hoffenheim coach Markus Gisdol.
Dusseldorf lost 3-0 at Hannover, and Augsburg took advantage by beating bottom side Greuther Fuerth 3-1 to secure Bundesliga survival.
On his club record 300th Bundesliga appearance for Hannover, American defender Steve Cherundolo set up Mame Diouf to score in the 36th minute.
Didier Ya Konan scored Hannover's second in the 61st and sealed Duesseldorf's fate in the 76th.
Franck Ribery scored two goals and set up two more as Bayern Munich came from behind to end their victorious Bundesliga campaign with a 4-3 win at Borussia Monchengladbach.
Javi Martinez reduced Bayern's deficit soon after but Harvard Nordtveit restored Gladbach's two-goal advantage in a frantic opening 10 minutes.
However, Ribery cut the deficit to 3-2 after 18 minutes and then hit an equalizer early in the second half, before setting up Arjen Robben's decisive goal on the hour.
The win sees Bayern finish the season on 91 points, the highest total in Bundesliga history and the perfect preparation for next weekend's Champions League showdown with Borussia Dortmund at Wembley.
Eintracht Frankfurt joined Freiburg in the Europa League thanks to a 2-2 draw with Wolfsburg, meaning Hamburg missed out as it lost 1-0 to third-placed Bayer Leverkusen.
Things looked worrying for Eintracht when it fell 2-0 down inside 20 minutes thanks to goals from Jan Polak and Diego. But the Wolves had Makoto Hasebe sent off in the 35th minute and Alexander Meier immediately pulled one back from the spot before Ricardo Rodriguez's last-minute own goal earned his side a draw.
"We're really looking forward to the coming games," said Frankfurt coach Armin Veh, who led the team to promotion last season. "But now I'm happy there are holidays. I'm knackered."
Bayer also went down to 10 men before the break, with Michal Kadlec seeing red in the 39th minute, but the game was won in the last minute thanks to Stefan Kiessling's goal.
"It was simply a great season," said Kiessling, whose side had already clinched third place.
Werder Bremen ended a miserable season that earlier this week cost Thomas Schaaf his job with a 3-2 loss at Nurnberg, while Stuttgart drew 2-2 at home to Mainz.
Information from Press Association and The Associated Press was used in this report.