AFP Sport looks as five key discoveries from the opening weekend of the 2015/16 Bundesliga season:

Douglas Costa seems to be worth the 30 million euros ($33.3m) Bayern Munich paid for him.

- The Brazil winger capped a superb Bundesliga debut with Bayern's last goal in Friday's 5-0 drubbing of Hamburg, but caught the eye with a wonderful piece of skill for Munich's third.

He chested down Mario Goetze's long-range pass right on the sideline, then put in a superb cross which Thomas Mueller fired home to show why Bayern paid Shakhtar Donetsk handsomely for his skills and pace out wide.

With no return date for Franck Ribery from an ankle injury, Costa is a sure starter on the left wing, especially after his superb late goal off his left boot capped an outstanding league debut.

Ingolstadt and Darmstadt are not just here to make up the numbers

- Newly-promoted Ingolstadt celebrated their debut in Germany's top flight with a 1-0 win at Mainz as Austria international Lukas Hinterseer scored their second-half winner.

Fellow new boys Darmstadt marked their return after a 33-year absence with a 2-2 draw against Hanover as winger Marcel Heller scored twice.

In each of the last five seasons, a team has been relegated after only one year in Germany's top flight, but both Darmstadt and Ingolstadt hope to halt the trend.

It looks like there will finally be a Bundesliga title race this season.

- After Bayern came out and hammered Hamburg on Friday, Dortmund beat Moenchengladbach 4-0 and Schalke routed Werder Bremen 3-0 on Saturday, before Wolfsburg comfortably saw off Eintracht Frankfurt on Sunday.

The Bundesliga has been a one-horse race for the last three seasons with Bayern winning the title at a canter by a margin of 25 points in 2012/13 -- the year they won the treble -- by 19 in 2013/14 and then 10 last season.

Bayern face both Wolfsburg and Dortmund in the space of a fortnight in the league from the end of September, then play Schalke away in November, and have also drawn Wolves in the second-round of the German Cup in October.

Borussia Dortmund's Julian Weigl is a teenager with a bright future

- The 19-year-old defensive midfielder made his Bundesliga debut in Dortmund's 4-0 drubbing of Borussia Moenchengladbach and already looks like a seasoned campaigner.

The teenager was alongside Germany international Ilkay Gundogan, with stars Shinji Kagawa, Marco Reus, Henrikh Mkhitaryan and Pierre-Emerick Aubameyang in front, but showed no nerves and was superb in the holding role.

A summer signing from second-division 1860 Munich, new Dortmund coach Thomas Tuchel had no problems promoting Weigl to the starting line-up ahead of Germany internationals Sven Bender and Gonzalo Castro.

"Julian has made a very good impression the whole time he's been here. He is thrilling us with his briskness and carefree attitude," said Tuchel, who is renown for pushing young talent to the fore.

"At the same time, he displays the ability to learn and to soak things up. He is a totally clear, cordial and open young man."

Schalke's Leroy Sane is a Germany star in the making

- Another 19-year-old caught the eye when he came off the bench and set up Schake's third goal with a superb run minutes after coming on.

The fleet-footed winger has a habit of scoring long-range goals and having won the ball in the Bremen box, sprinted the length of the field before providing Klaas-Jan Huntelaar with a simple tap as Schalke beat Bremen 3-0 away.

He scored a superb goal from the edge of the area at Real Madrid in the Champions League last season and it seems a matter of time before Germany coach Joachim Loew calls up the precocious talent.

Photo Credits : AFP