Borussia Dortmund face the first real test of their mettle as Bundesliga leaders on Sunday when they host Bayer Leverkusen, while Bayern Munich face a tricky tie at Darmstadt.

After the disappointment of last season's seventh-place finish Dortmund are back at the top of the table, ahead of rivals Bayern on goal difference, following four straight wins under new coach Thomas Tuchel.

Dortmund left it late to beat FC Krasnodar in their opening game of the Europa League group stage on Thursday and full-back Marcel Schmelzer is eager for their winning run to continue this weekend.

"We have unfinished business, not just against Leverkusen but in general (after last season)," Schmelzer, whose side were beaten 2-0 at home by Leverkusen last term, told the Bundesliga's official website.

"We're on the right track at the moment, though: we're focussed, working hard and desperately want to succeed.

"We know it's difficult to maintain the high level we're playing at, however, and so we want to make sure we keep a comfortable cushion over our rivals and remain in the Champions League places for as long as possible."

Pep Guardiola's star-studded Bayern squad will receive a warm welcome at Darmstadt's antiquated Merck Stadion on Saturday with the hosts looking for another upset win having stunned Bayer Leverkusen 1-0 last week at the BayArena.

Fresh from Wednesday's impressive 3-0 Champions League win at Olympiakos, Bayern turn their attention to beating Darmstadt to claim top spot in the table before Dortmund play 24 hours later.

Darmstadt are back in the Bundesliga after a 33-year absence and have never beaten Bayern in four previous meetings, the last of which was back in 1982.

Germany's World Cup winner Mario Goetze is set for another afternoon on Bayern's bench having been left out of the starting line-up in Greece, only to score as a substitute.

- 'aggressive pursuer' -

Bayern have the express intention of becoming the first team to win four-straight Bundesliga titles and despite winning all four games so far, they find themselves trailing Dortmund.

"It's great for the Bundesliga, but it's a bit unsettling to have such an aggressive pursuer. In fact, at the moment we're the ones doing the chasing," said Bayern striker Thomas Mueller, the league's top scorer with six goals in four games.

Guardiola has got off to the best start in any of his three years in Germany, but knows there is no guarantee of success in what is set to be a particularly competitive season.

"No team has ever won the Bundesliga four times in a row," he explained after Bayern's comeback win over Augsburg last Saturday.

"That's because achieving that is really difficult. Bayer Leverkusen lost at home to Darmstadt and VfL Wolfsburg could only get a draw in Ingolstadt."

The Darmstadt fixture sees the start of Bayern's run of five matches in 13 days.

The tally includes three key home matches against last season's league runners-up VfL Wolfsburg, a Champions League clash with Dinamo Zagreb, then Dortmund on October 4, which is warming up to be a battle royal.

"I can't imagine it’s been much fun for Dortmund to have been behind us in the last three seasons so of course, they're going to want to attack again," said Mueller.

Bottom side Borussia Moenchengladbach are at Cologne on Saturday looking for their first win of the season after a disastrous four straight league defeats having been beaten 3-0 at Sevilla on Tuesday in their opening Champions League match.

Fixtures (All times 1330 GMT unless stated)

Friday

Mainz 05 v Hoffenheim (1830)

Saturday

VfL Wolfsburg v Hertha Berlin, Hamburg v Eintracht Frankfurt, Werder Bremen v Ingolstadt 04, Cologne v Bor. Moenchengladbach, Darmstadt v Bayern Munich

Sunday

VfB Stuttgart v Schalke 04 (1330), Borussia Dortmund  -  Bayer Leverkusen, Augsburg v Hanover 96 (both 1530)

Source: AFP