Bayer Leverkusen moved eight points clear of Bayern Munich at the top of the Bundesliga after a narrow victory at mid-table Heidenheim.
Jeremie Frimpong put Xabi Alonso’s unbeaten side in front in first-half injury time with a deflected effort.
Amine Adli added a second after the interval, rounding goalkeeper Kevin Muller before slotting home.
Tim Kleindienst pulled one back for Heidenheim with four minutes left but Leverkusen managed to hold on.
Second-placed Bayern can reduce the deficit on their Bundesliga title rivals with victory at Bochum on Sunday.
Leverkusen’s victory means they have now gone a record-equalling 32 games without losing.
Bayern went undefeated in 32 consecutive competitive matches under Hansi Flick from 2019 to 2020.
Leverkusen are chasing their first Bundesliga title having finished as runners-up in 1996-97, 1998-99, 1999-2000, 2001-02 and 2010-11.