Bundesliga newcomers Elversberg kick-started their first top-flight campaign in style, stunning 2023-24 champions Bayer Leverkusen in a dominant 3-2 home victory, while Borussia Dortmund beat Hamburg in Saturday's late game.
Lukas Petkov and American striker Cole Campbell scored within 60 seconds of each other to put Elversberg 2-0 up before the 10-minute mark.
David Mokwa added another early in the second half. Leverkusen's Patrik Schick and Christian Kofane scored late, but it was not enough to prevent a famous victory for the minnows.
Elversberg has a population of just 13 000, making it the smallest town ever to have a German top-flight side.
Just 9 307 fans were able to watch the surprise win in the club's home ground, which is still under construction.
"It's an indescribable day," Elversberg captain Lukas Pinckert told Sky.
"We worked hard to earn the right to play in this league. The victory is deserved. I am incredibly proud of the team."
Leverkusen looked disorganised and lacked energy until late, showing coach Carles Martinez Novell has work to do after taking over in the summer.
DORTMUND SINK HAMBURG
Dortmund opened their season with a 2-0 home win over Hamburg but the comfortable victory was soured by a potentially serious injury to impressive debutant Giannis Konstantelias.
The Greece midfielder dazzled in his first Bundesliga game since arriving earlier in August, dribbling through the Hamburg defence before scoring Dortmund's second just after the break.
Konstantelias's goal came after teenage countryman Konstantinos Karetsas, another off-season arrival, had set up Dortmund's opener for Serhou Guirassy with just nine minutes gone.
Midway through the second-half, Konstantelias fell to the turf after a challenge and was immediately subbed out, grabbing his left knee.
Teenage Dortmund forward Samuele Inacio was shown straight red shortly after coming on for a dangerous challenge with 13 minutes remaining but the hosts held firm to claim victory.
"The complete diagnosis will come tomorrow, but the doctor told me it doesn't look good," Dortmund coach Niko Kovac told Sky.
Elsewhere, RB Leipzig cruised to a 3-0 home win over Borussia Moenchengladbach, with former Chelsea and France forward Christopher Nkunku setting up a goal on his return to the club.
Ridle Baku's first-half goal came against the run of play for Leipzig but the hosts took control when Antonio Nusa produced a stunning, curling effort early in the second half.
Nkunku, who scored 70 goals in a four-year spell at Leipzig before his Chelsea move, came on midway through the second half and set up a goal for former Gladbach forward Rocco Reitz just two minutes later.
Leipzig have been drawn to face Manchester City and Real Madrid on their return to the Champions League after missing Europe completely last season.
In the capital, Union Berlin came from 3-1 down to draw 3-3 with Eintracht Frankfurt, cancelling out Younes Ebnoutalib's hat-trick for the visitors.
Union's Tim Skarke scored in the third minute of stoppage time to level things up for the hosts.
Elsewhere, substitute Thijs Dallinga bagged a double and Germany starlet Said El Mala scored a dazzling solo effort as Cologne came from behind twice to beat Hoffenheim 3-2.
Hosts Mainz played out a scoreless draw with promoted Paderborn.
On Friday, Bayern Munich got their title defence off to a blistering start, steamrolling past Stuttgart 5-1 in a rematch of last season's German Cup final.