Hoffenheim could even secure its first appearance in the Champions League group stage if it holds on to third place - where it now stands after Benjamin Huebner scored in the last minute to snatch a 1-0 home win over Eintracht Frankfurt on Sunday. It has three more matches to play this season.
Huebner's late goal, a powerful header to Sebastian Rudy's corner, moved the side one point above Borussia Dortmund, which was held to a scoreless draw at home by Cologne on Saturday.
The goal was scored by the son of Frankfurt sporting director Bruno Huebner.
"A lucky win," acknowledged Hoffenheim backer Dietmar Hopp, the software billionaire whose finances helped his hometown club progress from minor leagues to the Bundesliga.
A co-founder of the SAP software giant, Hopp became the first private owner of a Bundesliga side when he took a majority stake in Hoffenheim in 2015. By then he had already spent an estimated 350 million euros on the team.
However, Hoffenheim's best appointment to date appears to be that of Nagelsmann, who took over in February 2016 after Huub Stevens stepped down for health reasons.
Then 28, Nagelsmann hadn't even earned his coaching credentials from the German football federation (DFB). But he saved the side from relegation and Hoffenheim is enjoying its best ever season this year.
The win over Frankfurt extended its unbeaten run at home to 16 games and ensured it beat its previous best-mark of 55 points from the 2008-09 season.
As a player, Nagelsmann lined up for Bavarian sides Augsburg and 1860 Munich before turning his attention to coaching. He spent almost a decade coaching the youth sides of 1860 Munich and then Hoffenheim, for which he was also assistant coach in 2012-13.
Earlier this year, Nagelsmann was named the German football federation's coach of the year for 2016.
Dortmund hosts Hoffenheim next weekend for a game that is likely to decide which side goes into the qualifiers and which secures automatic qualification for the Champions League.