Watzke told Sky Sport TV: "He hasn't lost a game yet. If he still doesn't lose any, we'd be stupid if we didn't keep it going."

Stoger was appointed as manager on Dec. 10, after the firing of Peter Bosz. The Austrian coach has since overseen four wins and three draws in the league, after eight games without a win under Bosz.

Watzke added: "We're satisfied with him. He's an extraordinarily good coach."

Stoger was himself fired the week before his appointment at Dortmund when Cologne failed to win any of their opening 14 matches. Stoger had secured promotion in 2013 for Cologne and oversaw steady progress before this season's poor start.

Dortmund gave Stoger a contract to the end of the season, leading to speculation they were looking to Hoffenheim's Julian Nagelsmann for next season, but Watzke told the station: "We haven't arranged anything with anyone."

Dortmund are third in the Bundesliga after two straight wins. They next face Atalanta at home in the Europa League on Thursday.