Xabi Alonso believed that Bayer Leverkusen's Bundesliga victory over Borussia Dortmund on Friday showed the improved discipline of the reigning champions. 

Leverkusen took the lead with just 24 seconds on the clock through Nathan Tella's early strike before Patrik Schick doubled their advantage in the eighth minute. 

Though Jamie Gittens halved the deficit, Schick grabbed his brace soon after to conclude a frenetic opening period at Westfalenstadion. 

Indeed, for the first time since March 2000 (9-1 against Ulm), Leverkusen netted three times in the first 19 minutes of a Bundesliga away match for the very first time. 

Serhou Guirassy's late penalty threatened a nervy ending for Alonso's side, but they were able to hold on to move within a point of leaders Bayern Munich in the table. 

Leverkusen were made to work for their win, registering just one shot on target in the second half with Dortmund in the ascendency to try and find the leveller late on. 

But Alonso believed that his team's showing highlighted their development as a squad throughout a campaign that had started poorly. 

"We are very satisfied with the performance and with the win," Alonso told a press conference.

"To come here and win with such a serious performance means that our development is important. A good start to the year."

Leverkusen have now won six consecutive Bundesliga games, while also extending their club-record unbeaten away league record to 25 matches (won 19, drawn six). 

Their triumph also brought an end to Dortmund's unbeaten record at home this season, leaving Nuri Sahin's side in sixth place ahead of the rest of the weekend's action. 

"We did the work in the beginning (of the game) and then we controlled it," added Alonso.

"We did it well with the ball, but we also did it really well without the ball. We did not concede much.

"It is a development of our game that we can compete in this way, to play here with this discipline against a top, top team in Europe."