"It's just unbelievable. If someone told me I would be in this situation six months ago, I wouldn't have believed them," an emotional Haller told DAZN.

Haller was diagnosed with testicular cancer shortly after signing with Dortmund and underwent four rounds of chemotherapy and two operations, missing six months before returning in January.

Dortmund sat in sixth place in January, but have lost just one of their 18 matches in the league since Haller returned.

Dortmund are now two points clear with one match remaining, a rare occurrence after a decade of Bayern Munich dominance.

The final round of games kick off at the same time next Saturday. To lift the Bundesliga shield for the first time since 2011-12, Dortmund will need a victory at home against Mainz only if Bayern win at Cologne.

If Bayern draw or lose, Dortmund will be champions even if they lose.

German tabloid Bild rejoiced after the win, running the headline "Haller-luja, Dortmund close in on the title".

Even though Dortmund dominated and Augsburg were reduced to 10 men late in the first half, the game was scoreless until the 58th minute, when Haller pounced on an error by a defender to score the opener.

He added another from a rebound with the clock winding down, sending the visiting fans into raptures. Julian Brandt struck in injury time to seal the result.

"We're very happy, but not completely satisfied," Dortmund manager Edin Terzic told DAZN. "We've got a next step we need to take".

A "happy and proud" Haller told DAZN: "We've got a huge chance to achieve something big."

Augsburg manager Enrico Maassen said "the red card was the crucial moment... you can give it, but that's a hard decision."

Dortmund, who came into the game knowing victory would put them in control of the title race, but made the trip without injured midfielder Jude Bellingham, were winless on the road since February.

Dortmund, who had scored 11 goals in their past two games, controlled the first half but could not find a breakthrough, Haller forcing a fingertip save from Tomas Koubek.

Shortly before half-time last-man Felix Uduokhai earned a red card, bringing down Donyell Malen on the edge of the penalty box.

Haller finally broke through for the visitors, snapping up a loose ball before spinning and threading the ball into the far corner.

With just over five minutes remaining, Haller repeated the trick, pouncing on a rebound from a Marco Reus shot to put Dortmund 2-0 up, sending the visiting fans into a chant of "German champions, only Dortmund".

With the clock winding down, Dortmund captain Mats Hummels was helped off the field after taking a boot to the face.

The centre-back's replacement, Nico Schlotterbeck, put the ball through for Brandt to score a third.

Stuttgart stay alive

Earlier, a goal and two assists from substitute Chris Fuehrich gave Stuttgart a massive boost in their relegation fight, with a 4-1 win away at Mainz.

Brought on with 30 minutes remaining and the scores locked 1-1, Fuehrich laid on a goal for Serhou Guirassy just two minutes later, before adding one of his own.

The winger set up another goal in injury time for Tanguy Coulibaly to take his side from the relegation places to the safety of 15th with one matchday remaining.

In Sunday's late game, sixth-placed Bayer Leverkusen can improve their chances of European football next season with a win at home against Borussia Moenchengladbach.