One Hamburg SV fan suffered "life-threatening injuries" and 19 more were seriously injured in celebrations after the team's return to the Bundesliga, local fire services said on Sunday.
The Hamburg Fire Department launched what it called a "major emergency response" to contend with Hamburg fans celebrating promotion on Saturday, when thousands of supporters stormed the field.
Some 44 supporters needed medical treatment, including 25 who were taken to local hospitals, of whom five had just minor injuries.
Hamburg clinched its long-awaited return to the top division with a 6-1 rout of Ulm, ensuring they will finish in the top two of Germany's second division and automatic promotion to the Bundesliga.
Hamburg endured six seasons of just missing out on promotion since their demotion from the top division before success at the seventh attempt.
The club was previously known as "der Dino" because it was the last surviving member of the Bundesliga to have played every season since its formation in 1963.
They were finally relegated in 2018 after several close calls.