What happens when an unstoppable force hits an impenetrable wall? We are about to find out this coming Saturday, when Bayer 04 Leverkusen play host to league leaders FC Bayern München (kick off 18:30CET/17:30GMT).

The latest encounter between Die Werkself and the record titleholders is set to be an explosive one, not least because of the impending face-off between two of the sharpest shooters in world football: Javier 'Chicharito' Hernandez and Robert Lewandowski. With 32 goals between them, the two marksmen will go on the prowl at opposite ends of the same field this weekend in Matchday 20’s standout fixture.

Read: Leverkusen vs FC Bayern preview

'Irreplaceable'

© gettyimages / Volkmann

With 45 per cent of his side's goals so far this season, Chicharito's contribution to Bayer's campaign has been substantial. "We’re delighted how it’s panned out, that much is certain," Leverkusen managing director Michael Schade told bundesliga.com. "Chicharito is scoring so consistently. It was a wonderful transfer - others definitely envy us. There's a real buzz around him, but we also know we rely on Chicharito. He’s really happy here. He's irreplaceable for us."

On Matchday 19, it was Chicharito's prospering partnership with Stefan Kießling which helped Leverkusen pick up the points that lifted them fourth heading into Saturday’s battle with Bayern. The two strikers supplied all of their side's three goals against Hannover 96, and it is they who Bayern's injury-depleted defence will have to keep close guard of. "Everyone knows how important they both are as players," explained Leverkusen midfielder Kevin Kampl. "They've both got so much experience, one abroad and one in the Bundesliga. They go well together."

Read: Head here for our mini-site on Chicharito

'Indisputable'

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No less can be said of Lewandowski's partnership with Thomas Müller. Together, they have scored more goals than 15 of the 18 Bundesliga clubs have amassed this season, Leverkusen included. Their 33 combined strikes make them the most prolific partnership ever at this stage of a Bundesliga season, with more than the legendary Gerd Müller-Uli Hoeneß axis, or Müller and Karl-Heinz Rummenigge managed in one of the attacks reputed to be one of the fiercest in the history of the game.

"Thomas is a fantastic player and it's great fun to be on the field with him," Lewandowski waxed lyrical about his partner in crime. "He always looks for the right pass and that's why things work so well between us. I hope our partnership will get even better." Müller, for his part, told UEFA.com that Lewandowski's "qualities are indisputable", as he enjoys sharing in his limelight.

Read: Click here for our mini-site on Robert Lewandowski

Pep's defensive dilemma

Goals therefore appear programmed, even if the meanest defence is up against the joint third most water-tight in the league. With just nine goals conceded in 19 games, it is hardly surprising that Bayern are once again setting Bundesliga benchmarks. That record has been largely sustained with Jerome Boateng in a form which has elevated him to world class status.

© gettyimages / Adam Pretty/Bongarts

A groin injury picked up by the 27-year-old in the opening fixture of the Rückrunde has potentially weakened Bayern's rearguard, though, and the loss of Javi Martinez for a month will only have added to Pep Guardiola's defensive dilemma. Transfer deadline day saw 2007 Bundesliga winner Serdar Tasci drafted in as cover, while the Catalan experimented, successfully, with a back three in the 2-0 win over TSG 1899 Hoffenheim last weekend. Who is to say that the tactician does not have other tricks up his sleeve to keep Chicharito and Kießling at bay?

Unhappy memories

If Guardiola succeeds in doing so, he could achieve something he has not yet managed since taking charge of Bayern in 2013: preventing Die Werkself from scoring against his side at the BayArena, a location where he has found less hospitality than anywhere else in Germany in terms of results. A 1-1 draw on his first visit in 2013 was followed by a 2-0 loss back in May, leaving him still waiting for his first win in Leverkusen.

 Victory on Matchday 20 would arguably represent the biggest step yet towards a third straight Bundesliga title for Guardiola, and a fourth for Bayern. Their perennial rivals from the west have been a thorn in Bayern's side in recent years, though, and they have , not to mention two sharp-shooters to help them achieve that target.

Competition: Win the official TORFABRIK match ball from Leverkusen vs FC Bayern