Borussia Dortmund coach Niko Kovac has urged his side to stay focused after a 2-0 win at Mainz ensured the German giants continued their unbeaten start to the campaign.

Goals from Daniel Svensson and Karim Adeyemi gave Dortmund an ideal advantage in the first half of Saturday's Bundesliga matchup.

Mainz goalkeeper Robin Zentner saw red in the 67th minute, which rounded off a comfortable afternoon for the Yellow and Black, who are looking to keep pace with Bayern Munich in first. 

Dortmund have now kept a clean sheet in four of their five league games, more than any other team in the Bundesliga so far, and have 13 points on the board.

“It turned out exactly as we wanted: we wanted to get the win here in Mainz. The team played with great discipline and organisation throughout the 90 minutes," Kovac said. 

"We scored at the right moments and had a bit of luck with their shot that hit the post, which then led to our first goal.

“The Bundesliga is exciting. We’re really only focused on ourselves and we want to stay where we are.

" I know how things are in life and in football. That’s why we are staying focused. We will continue to work hard."

Julian Brandt set up both goals, continuing his strong start to the Bundesliga season, with no Dortmund player registering more. 

"We’ve kept a clean sheet for the fourth game in a row. I’m also delighted that Jule Brandt – after Serhou [Guirassy] had to come off – decided the game with two truly fantastic passes," Kovac added. 

An injury to Guirassy, which forced him out of the warm-up, was the only blot on a good day for Dortmund, who host Athletic Bilbao in the Champions League on Wednesday.