WATCH Genoa v Napoli and EVERY Serie A game LIVE & EXCLUSIVE on beIN SPORTS | Sign up here and save up to $60 on our Annual Pass Now | AU | NZ

Having secured three promotions in five seasons to reach the top division, Elversberg got off to a flying start when Lukas Petkov and Cole Campbell netted inside nine minutes.

David Mokwa made it 3-0 shortly after half-time, but the hosts had to survive an attempted comeback as late goals from Patrik Schick and Christian Kofane ultimately proved redundant.

Leverkusen loanee Francis Onyeka haunted his parent club early on. He held up play well before offloading towards the edge of the box for Petkov, whose left-footed drive caught Mark Flekken flat-footed for the opening goal.

Immediately from kick-off, Edmond Tapsoba was caught in possession at the back, allowing Campbell to drive forward and fire into the bottom-left corner.

Leverkusen almost responded when Aleix Garcia's deflected free-kick clattered the crossbar, with Afonso Moreira unable to head home on the rebound.

However, in an almost identical repeat of the first half, Leverkusen were caught napping after the interval when Petkov’s right-sided cross found Mokwa to bundle home at the near post in the 47th minute.

Schick twice headed off target as Leverkusen looked to get back in the game, but the striker eventually pulled one back with 13 minutes remaining, flicking in smartly from Ibrahim Maza's diverted shot.

Kofane then pounced on a 91st-minute rebound after Victor Boniface was denied by the woodwork, but Elversberg dug deep to earn a memorable victory.