It was all going smoothly as the half-time whistle peeped at the Allianz on Wednesday night.

Leading through Robert Lewandowski’s tidy finish, Pep Guardiola was getting better of Jürgen Klopp in his final Der Klassiker. Klopp's Dortmund couldn’t get anywhere near Bayern, and Arjen Robben was on the bench after his spell out with injury.

But then it went horribly wrong. Denied a clear penalty at 1-0 up, Dortmund then equalized with virtually their first meaningful attempt, and the panic set in. Robben was summoned from the bench in order, only for the Dutchman to be injured again, and have to be substituted himself.

Extra-time beckoned, Lewandowski got himself injured too, and Dortmund took Bayern to penalties: only for the hosts to inexplicably fluff their lines, miss every penalty they took and be dumped out of the cup in their own home by their biggest rivals in recent years.

The scars were shown fully the following morning; Robben tearing his calf muscle to end his season prematurely, and Lewandowski breaking his cheekbone and jaw. Just before the timely visit of Barcelona, who finally seem to have moved on from Guardiola. How Hans-Wilhelm Müller-Wohlfahrt must have smirked.

Yet Roger Schmidt and Leverkusen will not take the visit of the newly crowned champions lightly; the last time they were embarrassed, Hoffenheim were dealt with and Porto were completely swept away.

But Leverkusen won’t let their opponents build from the back, with Schmidt’s troops settled into their high-pressing game and ready to get back into the top three. With Bayern having one eye on Barca this Wednesday, Schmidt could take full advantage.

Last time out

In the reverse league game at the Allianz Arena in the first week of December, Bayern had a monopoly over possession, yet couldn’t find any way through the Leverkusen wall in front of their goal. It took until the sixth minute of the second half as Franck Ribery finally broke the deadlock and Bayern took an important 1-0 win over a member of the chasing pack.

Team news

Robben is out with the aforementioned calf injury, and Lewandowski is a doubt with his jaw trouble too, to add to an increasing injury list with the names of Franck Ribéry, David Alaba, Holger Badstuber and Tom Starke. However, the return of Javi Martínez from a nine-month lay-off would be a timely return indeed.

Bayer Leverkusen will of course be missing Emir Spahic after his contract was terminated with a fracas with a steward in the DFB Pokal quarter-final loss to Bayern, and will also be missing Kyriakos Papadopoulos, Gonzalo Castro and Robbie Kruse.

They said

Roger Schmidt was keen to point out the strength of Bayern’s squad despite the numerous injuries, telling reporters in their press conference “Bayern will still field a very good side.

“I don’t think we’re in with a better chance just because a number of players are sidelined. All the players in the squad are top level."

Despite securing a top four place, the aim for Bayer is still to achieve top three, and Schmidt says they need four big performances to do so.

“It’s a great achievement,” he said, “to secure fourth place with five games to play but third place is obviously the target now. We need to produce four top performances to achieve that.”

With one eye on the trip to Catalonia next week, Guardiola was relatively relaxed about Saturday’s late fixture, saying “Leverkusen are fighting for a direct Champions League qualifying position, but we have no more targets.

“We’ve done it already. The Bundesliga is over, and we’ve already won it, so we’re focused on next Wednesday.”

The game against Barcelona will take precedence, with the Bayern boss looking to rotate, if possible.

“Wherever we can rotate, we will. But we have 15 players at the moment.”

Yet no one has seemed to have told his players that this game isn’t important, with Thomas Müller in bullish mood ahead of the trip to the Bayer Arena, claiming “We will definitely show up and try to win.”

Key players

With the injuries to Ribéry, Robben and Lewandowski, the goalscoring mantle will fall to Thomas Müller. The 25 year-old German international has scored 13 league goals this season, matching his best tally, and will be hoping to make this season his best yet in front of goal.

But Müller will face a stern test; Leverkusen’s goalkeeper Bernd Leno has been just as impressive this season, having kept 14 clean sheets, and has been a key part in why Leverkusen are undefeated in nine going into the game.