Axel Witsel believes Borussia Dortmund have no room to hide in the Bundesliga title fight after forming a squad capable of challenging Bayern Munich.

Dortmund have strengthened considerably in the close season, recruiting established performers Thorgan Hazard, Nico Schulz and Julian Brandt, along with the vastly experienced Mats Hummels.

The latter has rejoined the club from Bayern Munich, who capitalised on Dortmund's collapse to win the title by two points on the final day last season.

Lucien Favre's side had been the clear frontrunners until February and midfielder Witsel says there can be no excuses come the start of the new campaign.

"I want to win titles with this team," Witsel told Kicker.

"A club like Borussia Dortmund must have that as a goal.

"I think we are stronger than last season. The championship is therefore a realistic goal. We must not hide.

"But we still have to prove we are stronger. You have to play at a top level all the time and you need courage. Otherwise, don't bother trying."

The return of World Cup winner and five-time Bundesliga champion Hummels after three successful seasons in Bavaria could prove especially useful in guarding against ill-timed stumbles.

"As far as I can tell it's as if he has never been away," Witsel said.

"It's easy for me to share the pitch with him. He's technically very good, I can give him the ball in any situation

"He's a leader - we can use another one of those guys - and he'll feel the impact he has on training right from the start.

"The more leaders the better."