Julian Brandt hailed Borussia Dortmund's threat from set pieces after a clinical display against Mainz.

Julian Ryerson registered all four assists in the victory, with three of those goals coming from set pieces as Dortmund moved within three points of Bundesliga leaders Bayern Munich.

Ryerson is only the fourth player since detailed data collection began in 2004-05 to register four assists in a Bundesliga match. For Dortmund, only Pascal Gross had achieved this before, against Union Berlin last season.

Dortmund have now won each of their last six games in the German top-flight, helping them get back into the title race.

Brandt believes the improvement in set pieces has been a key reason for their recent form.

The midfielder told RTL: "We were very dangerous from set pieces.

"The second half was less spectacular, but all the more secure for it. We place a lot of importance on set pieces, and we knew after the first half of the season that we still had potential to improve in this area.

"Both the target players and the corner takers are doing a good job at the moment.

"Goals from set-pieces often unlock the game for us. Today [versus Mainz], against Wolfsburg, and also in one or two other games before that."

Only Bayern's Michael Olise (16) has provided more assists in the Bundesliga than Ryerson (11) this season, and the wing-back was quick to praise his team-mates for their role in the goals.

"It was nice to take an early lead again, quickly score the second, and then the third before half-time," Ryerson told Sky. 

"Four goals feel very good. I have to put the ball on target, and the others have to run there. When we score from a set piece, it's not just my assist or the goalscorer, it's several people involved in the play."