Stuttgart were held to a goalless draw at home by Hoffenheim on Saturday, missing a chance to end the calendar year in the top four.
The stalemate means this year's surprise packages Hoffenheim, who only just beat relegation last season, stay fourth, with Stuttgart a point behind in sixth.
Bayer Leverkusen can leapfrog Hoffenheim into the top four by avoiding defeat at RB Leipzig in Saturday's late match.
Stuttgart had a chance to take the lead just before halftime when Tiago Tomas' close-range effort was saved by Hoffenheim's Germany goalkeeper Oliver Baumann.
Deniz Undav headed in a free-kick in stoppage time, but his goal was ruled out for a narrow offside.
Eintracht Frankfurt's struggles continued with a 1-1 draw away against Hamburg.
Frankfurt equalised through Hugo Larsson after Albert Sambi Lokonga had given the hosts an early lead.
Arsenal loanee Fabio Vieira's late winner for Hamburg was ruled out by VAR for offside.
In the top-four fixtures last season, Frankfurt sit seventh, having struggled defensively this term. No team has conceded more than Frankfurt's 30 goals in the Bundesliga this season.
Promoted after seven seasons in the second division in the summer, Hamburg have been strong at home, with 14 of their 16 points coming at their 57 000-strong Volksparkstadion.
A stoppage-time goal from Andras Schaefer took Union Berlin to a 1-0 win away against 10-man Cologne, helping the eighth-placed side keep pace with the European spots.
Elsewhere, Freiburg came from behind twice to beat Wolfsburg 4-3, despite home striker Dzenan Pejcinovic scoring a hat-trick, while Augsburg and Werder Bremen played out a scoreless draw.
On Sunday, defending champions Bayern Munich need a win away at Heidenheim to restore their nine-point lead atop the table over second-placed Borussia Dortmund.