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Dortmund finished second in the Bundesliga but have won the German Super Cup this season

It has been seven years since a team other than Bayern Munich has won the Bundesliga but the German giants could be set to see their domestic dominance come under threat this season.

Bayern kick off the new campaign on Friday night against Hertha Berlin.

But they struggled to strengthen as much as they would have hoped in the transfer market while their title rivals Borussia Dortmund appear to have bought wisely.

Meanwhile, former Huddersfield manager David Wagner will hope to rejuvenate a Schalke side that has lost its way in recent times, while all eyes will be on Paderborn after their "miracle return" to the top flight.

BBC Sport takes a look at some of things to watch out for in this season's Bundesliga.

Dortmund to finally break Bayern's stranglehold?

Dortmund won back-to-back titles in 2010-11 and 2011-12 but since then top spot has belonged to Bayern Munich.

However, Lucien Favre's side pushed Bayern close last season, taking the title battle to the final game having at one stage been nine points clear.

And they have already beaten Bayern to win the German Super Cup this month.

Dortmund got their transfer business completed early over the summer, bringing back defender Mats Hummels from Bayern and Germany full-back Nico Schulz from Hoffenheim to shore up a defence that was prone to letting in costly late goals last season.

Germany midfielder Julian Brandt and Belgium forward Thorgan Hazard have also arrived from Bayer Leverkusen and Borussia Moenchengladbach respectively.

"The way that Borussia Dortmund are talking, I think they will be close," Bundesliga journalist Archie Rhind-Tutt told BBC Radio 5 Live's Football Daily Euro Leagues podcast.

"Dortmund have changed their rhetoric. At the start of last season it was all about rebuilding.

"Even when they were nine points clear they were still not saying the title was their aim and that is something they admitted was a mistake in the summer."

'Sancho to be the star for Dortmund'

Jadon Sancho made 43 appearances for Dortmund last season, scoring 13 goals

On top of the new additions, big things are expected once again of exciting England winger Jadon Sancho.

The 19-year-old was the top assist maker in the Bundesliga with 14 and, according to Rhind-Tutt, he is undoubtedly the star player in the Dortmund team.

"I don't think I can see how this season can go wrong for him," he said.

"I think he is one of the best, if not the best, player in the Bundesliga in a one-on-one situation."

Problems for Bayern?

Bayern Munich spent the summer pursuing Manchester City forward Leroy Sane, who was seen as the club's number one target to fill the void left by Arjen Robben and Franck Ribery.

However, an injury for Sane scuppered that move and leaves Bayern still looking to bring in a marquee signing before the German transfer window closes on 2 September.

Rhind-Tutt added: "Bayern only lost four games last season but, given the fact they have not made that star signing they wanted to, I think they may have a slightly more tough time of it or, more accurately, their coach Niko Kovac might have a tough time of it."

Philippe Coutinho has been heavily linked with both Bayern Munich and PSG

Bayern have reportedly external-link turned their attention to Barcelona playmaker Philippe Coutinho, although could face competition external-link for the Brazilian's signature from Paris St-Germain.

They have also signed Croatia winger Ivan Perisic on a one-year loan from Italian club Inter Milan.

"I think Coutinho would give Bayern something a little different up there but it is still a weird scenario for Bayern because they are used to getting their business done early," Rhind-Tutt said.

"They have put themselves under a lot of pressure and it still feels like something is missing from Bayern right now."

Wagner to get a tune out of the underachievers?

David Wagner left Huddersfield in January

Schalke appointed former Huddersfield boss David Wagner in the summer and the 47-year-old German is immediately under pressure to turn things around for the perennial under-achievers.

The club won the Uefa Cup in 1997 when Wagner was part of the squad but have had little success since then. They were runners-up in the Bundesliga two seasons ago but finished 14th in 2018-19.

"Success in the words of David Wagner would be a top-half finish," said Rhind-Tutt. "That says something when you are a club of Schalke's size.

"They have a difficult start - their first two games of the season are Moenchengladbach away - and they are going to be one of the sides to watch out for this season - and then they have Bayern at home.

"If they are on zero points after two games it will be a sticky situation for him."

Brits abroad in the Bundesliga

Ademola Lookman joined Leipzig from Everton for £22.5m in the summer

As well as Sancho, Ademola Lookman will once again feature in the Bundesliga having made the switch from Everton to RB Leipzig.

The 21-year-old had a successful spell on loan at the club in the 2017-18 season, scoring five goals in 11 league games and will be hoping to kick on in his first full season as a permanent player.

Lookman's former Everton team-mate Jonjoe Kenny was signed on loan by Wagner for Schalke in the summer and is set to be his new manager's first-choice right-back.

Joining Lookman at Leipzig this season is defender Ethan Ampadu after the Welshman has moved on loan from Chelsea.

Others to keep an eye on are former Manchester City youth player Rabbi Matondo at Schalke, Augsburg defender Reece Oxford and midfielder Lewis Baker, who is spending the season at Fortuna Dusseldorf from Chelsea.

'The miracle Bundesliga return'

SC Paderborn's only season in the Bundesliga came in 2014-15 when they topped the table after four games

Supporting a football team can often be a roller coaster for fans, but SC Paderborn have taken that to an extreme over the past five years.

Climbing from amateur football to the Bundesliga summit in a decade, a crushing three successive relegations sent the German club spiralling down - before making their return to the top flight via a huge slice of luck inspired one of football's most intriguing tales.

They face Bayer Leverkusen in the German top flight on Saturday and you can read more about their story here.