Piero Hincapie scored in stoppage-time to snatch all three points for Xabi Alonso's side, which remarkably remains unbeaten in the league this season and is seven points clear of second-placed Bayern Munich, which plays Werder Bremen on Monday (AEDT).

Leipzig was well on top in the early stages, confirming Alonso's fears that it would be a tough opponent at home. The hosts missed two excellent chanes to go ahead, but Xavi Simons made sure they did with a superb strike on the spin after he'd controlled the ball twice in the air in the seventh.

As if things weren't bad enough for Leverkusen after going behind, Jeremie Frimpong was then taken off injured after half an hour.

But half-time is just what the visitors needed, and with Alonso's words still ringing in their ears after the break, Nathan Tella equalised within two minutes of the restart, tapping in unmarked from Alejandro Grimaldo's cutback.

Florian Wirtz came close to putting Leverkusen ahead, forcing Janis Blaswich into a great save on 55 minutes, but it was Leipzig that would go back in front against the run of play through Lois Openda, who completed a swift counter-attack moments later with a one-touch finish.

The lead lasted only seven minutes, though, as Leverkusen again drew level throgh Jonathan Tah, who wrestled clear of the Leipzig defenderd from a corner to head home from Jonas Hofmann's delivery.

With stoppage-time barely a minute old, Hincapie completed the sensational comeback when he stabbed home at the far post as Leipzig again failed to deal with a corner, this time from the other side as Grimaldo delivered, sending the visitors into wild celebrations and cementing their credentials as serious title contenders.