Dortmund, meanwhile, are suddenly back in the title picture after a good run of form under Edin Terzic has helped them move to within five points of league leaders Bayern Munich.
Indeed, having been promoted from assistant coach to caretaker manager after the dismissal of Lucien Favre as Dortmund manager in December, Terzic is making a strong case for the job on a full-time basis having won four of his five games in charge so far.
BVB had every inch of their attacking swagger back on the way to beating RB Leipzig 3-1 away from home on Saturday, with Erling Braut Haaland, Marco Reus and Jadon Sancho putting on a counter-attacking masterclass after a disappointingly dour first half.
First Haaland raced through before cutting the ball back to Reus, whose delicate touch guided the ball towards Sancho.The England winger seemingly had his birth city's bus service in mind all along; after waiting so long to score his first league goal of the season, the 20-year-old made it two goals in two games with a decisive strike into the bottom corner.
After Haaland and Dani Olmo both missed good opportunities for either side, the Norway striker capped one of the goals of the season so far having taken five Leipzig opponents out of the game with dazzling feet in the build-up. Emre Can backheeled the ball to Sancho, whose devilishly in-swinging cross laid the ball on a plate for Haaland to power Dortmund into a two-goal lead.
The 20-year-old then wrapped up the three points with his eighth brace of the season for club and country after rounding Peter Gulasci in trademark fashion, before Alexander Sorloth scored a late consolation goal for the hosts. There is little doubt that Mainz have a serious job on their hands to contain the Golden Boy award winner.
Mainz recently appointed their fourth head coach of the campaign in the shape of Bo Svensson, with the former Denmark international potentially a popular choice with the Mainz fanbase having spent seven years at the club as a player between 2007 and 2014.
Sentiment will only get Svensson so far, though, with his side deeply embroiled in a relegation battle which, on current form, they appear to have very little chance of getting themselves out of.
Indeed, Mainz's shortcomings were there for all to see in Svensson's first game in charge against Eintracht Frankfurt last weekend, with Die Nullfunfer succumbing to a 2-0 loss. However, both goals were courtesy of questionable refereeing decisions, with Andre Silva twice proving the beneficiary from the penalty spot.
Given that Mainz have collected a miserly one point from the last 23 matches in which they have conceded first, Svensson may actually have been mildly pleased with the spirit and improvement of performance his players showed after the half-time interval, too. Jonathan Burkhardt twice came close to levelling proceedings, with Svensson sure to be hoping for more from Robert Quaison and Jean-Phillipe Mateta in the coming weeks.
Borussia Dortmund Bundesliga form: DLWLWW
Borussia Dortmund form (all competitions): LWLWWW
Mainz 05 Bundesliga form: LLDLLL
Mainz 05 form (all competitions): LDLLLL
Dortmund's impressive victory at Leipzig came at a major cost, with Axel Witsel having to undergo surgery to repair an Achilles tendon rupture in recent days. The midfielder could miss the rest of the season, with Can likely to be handed a more regular starting berth in the Belgian's place.
With a testing trip to Bayer Leverkusen on Tuesday, Terzic may be tempted to rest a few players given the significance of that fixture and Mainz's dire form of late, but equally could opt to substitute players if his side can gain a comfortable lead.
Borussia Dortmund possible starting lineup:
Burki; Meunier, Akanji, Zagadou, Guerreiro; Can, Delaney; Sancho, Brandt, Reyna; Haaland
Mainz 05 possible starting lineup:
Zentner; Brosinski, St. Juste, Hack, Niakhate; Latza, Barreiro; Szalai, Quaison, Boetius; Mateta
We say: Borussia Dortmund 2-0 Mainz 05
Dortmund are unlikely to have as much space in behind Mainz's defence as they found at Leipzig, but should still have too much strength for their opposition.
Much will depend on how strong Terzic goes with his team selection ahead of a difficult match at Leverkusen on Tuesday, but any squad players coming into the side are still a cut above most of Mainz's options.