Bundesliga Preview: Bayer out to stay in Euro hunt
Lewandowski was named coach of Leverkusen on a temporary basis on Monday after Sami Hyypia was sacked following the club's disappointing defeat to relegation candidates Hamburg last week.
The defeat left Leverkusen in fifth position in the Bundesliga, behind Borussia Monchengladbach and the final Champions League qualifying spot on goal difference with nine games remaining.
Leverkusen, who have only won one of their past nine league fixtures, have the opportunity to get their campaign back on track when they host Hertha Berlin on Sunday.
"We're going to have to turn a few screws to get results as quickly as possible," Lewandowski said.
"We can't just carry on the way things are."
Lewandowski added: "It's a chance for everybody to prove themselves. We don't have much time, so we all have to react."
Defeat could prove extremely costly for Leverkusen, especially if Monchengladbach get the better of relegation-threatened Stuttgart, who are above the drop zone on goal difference.
The Wolfsburg camp will be keeping a close eye on proceedings at BayArena, with Dieter Hecking's men just one point adrift in sixth spot.
Wolfsburg are at home to second-botton Nurnberg, who are one point adrift of safety.
Meanwhile, recently crowned champions Bayern Munich entertain rivals Borussia Dortmund in the match of the round.
Bayern claimed back-to-back league crowns with seven games to spare, though Dortmund are still playing for second position.
Jurgen Klopp's team are three points ahead of third-placed Schalke, who are in action against Eintracht Frankfurt on Friday.
In other fixtures over the weekend, Hamburg can continue their surge away from the relegation zone with victory over fellow strugglers Hannover.
Hamburg climbed off the foot of the table to within one point of safety and two adrift of free-falling Hannover after upstaging Leverkusen in round 29.
Elsewhere, four points separate Freiburg and cellar dwellers Eintracht Braunschweig heading into Saturday's match.
Mainz welcome Werder Bremen to Coface Arena on Saturday, while Hoffenheim go head-to-head with surprise packets Augsburg on Monday.