Bayern on title course after putting six past Schalke
Dortmund host Borussia Moenchengladbach and a win can cut Bayern's lead to one point with two games remaining this season.
A measured Bayern manager Thomas Tuchel said his side "made a step in the right direction -- our buried self confidence is coming back" but said "there's no reason for euphoria, we'll be tested again on Saturday (against RB Leipzig)."
Veteran Bayern captain Thomas Mueller, given a starting berth after being named on the bench in his side's last two matches, settled the home side's nerves early, slotting in after 21 minutes, his first goal in eight matches.
Joshua Kimmich doubled Bayern's lead shortly after, converting a penalty despite losing his footing after Jamal Musiala copped an arm in the box.
Any slim hopes Schalke had of a comeback were snuffed out early in the second stanza, Gnabry collecting a pass from Joao Cancelo and hammering in at the near post scored for the third consecutive match.
Gnabry added another midway through the second half, French teenager Mathys Tel made it five and Noussair Mazraoui scored his first goal in Bayern colours to put the home side on course for an 11th straight Bundesliga title.
The loss leaves Schalke, who had climbed out of the relegation places for the first time since September with last week's win at Mainz, in the relegation playoff spot with three games remaining.
Union 'keep dreaming'
Elsewhere, Union Berlin solidified their hopes of a first Champions League appearance, leapfrogging RB Leipzig into third and going three clear of fifth placed Freiburg with a 4-2 home win.
Union set up the victory with a first-half blitz, Sheraldo Becker scoring twice in two minutes after Kevin Behrens opened the scoring with five minutes gone.
Freiburg's Manuel Gulde pulled one back ten minutes into the second half and a comeback looked on when Vincenzo Grifo chipped panenka in from the spot with 20 minutes remaining.
Becker however snuffed out the visitors' hopes, collecting the ball on the break and finding an unmarked Aissa Laidouni who knocked in Union's fourth.
"The fans can keep dreaming" said an elated Union manager Urs Fischer "we had to go for it today".
Eintracht Frankfurt won their first game in 11 matches despite manager Oliver Glasner's stadium ban, thrashing Mainz 3-0 at home, thanks to goals from Daichi Kamada, Aurelio Buta and Randal Kolo Muani.
Frankfurt, who midweek decided to part ways with Glasner at season's end despite the Europa League holders reaching the German Cup final, responded in emphatic fashion to leapfrog their derby rivals.
Bochum took advantage of Schalke's poor result in Munich, beating Augsburg 3-2 at home to lift themselves past the Royal Blues out of the relegation places by a single point.
Elsewhere, Wolfsburg responded from Sunday's 6-0 thrashing by Dortmund to beat Hoffenheim 2-1 at home, moving into sixth place, the Europa Conference League spot.
The loss leaves Hoffenheim just two points clear of the relegation spots with two games remaining.