League leaders Schalke gave the rest of the Bundesliga hope as they succumbed to a 1-0 defeat to Bayer Leverkusen on Sunday.
Schalke could have gone seven points clear at the summit but Stefan Kiessling's goal five minutes from time saw them beaten at Arena AufSchalke.
However, Werder Bremen failed to make up significant ground on Schalke as they were held to a 2-2 draw by Borussia Monchengladbach.
Bremen remain in third - two points behind Stuttgart - after twice letting a winning position slip at Borussia-Park.
Pierre Wome (11) and Jurica Vranjes (84) twice gave Bremen the lead, but Michael Delura (17) and Nando Rafael (90) gave the hosts a share of the points.