Borussia Dortmund are set to appoint Niko Kovac as the club's new head coach.

The Bundesliga club sacked Nuri Sahin last week after their Champions League loss at Bologna was a disappointing fourth successive defeat.

Kovac, 53, has been out of work since departing Wolfsburg in March last year.

"We have reached an agreement in principle with Niko Kovac, he will take over the team on Sunday," Dortmund's managing director Lars Ricken told broadcaster DAZN.

Ricken was speaking before Dortmund secured progress to the Champions League play-off round with a 3-1 home win over Shakhtar Donetsk on Wednesday night.

Former Croatia international Kovac has also had coaching spells at Eintracht Frankfurt, Bayern Munich and Monaco since managing his country between 2013-2015.

Interim coach Mike Tullberg, who stepped up from the club's under-19 team following Sahin's sacking, will take charge when Dortmund visit Heidenheim in the Bundesliga on Saturday.

Dortmund are 11th in the German top-flight with seven wins from their 19 league games this season.