Frankfurt, which drew 1-1 at home to Chelsea in the first leg of their semifinal on Thursday, was second best in every aspect from the first minute and only holds the last place for Champions League qualification through goal difference.
But even that looked under threat as Leverkusen became the first team to score six goals in one half since Borussia Moenchengladbach thrashed Borussia Dortmund 12-0 in April 1978. Sunday’s match was the first time seven goals had been scored in the first half of a Bundesliga game.
"It was a pitch black day for us and one of the worst for me as coach," Adi Huetter said.
Kai Havertz began the rout in the second minute, and Julian Brandt made it 2-0 in the 13th.
Filip Kostic pulled one back a minute later but Frankfurt fell further behind to two goals from Lucas Alario and another from Charles Aranguiz before Martin Hinteregger’s own-goal in the 36th.
Huetter reacted by bringing on Luka Jovic and Mijat Gacinovic, upsetting his plan to rest the players before facing Chelsea away on Thursday.
Frankfurt remained fourth on goal difference ahead of Leverkusen, which claimed its fourth straight win. Borussia Moenchengladbach and Wolfsburg are two points behind and Hoffenheim one further point back. There are two rounds left.
Schalke’s 0-0 draw at home to already safe Augsburg assured the team of Bundesliga survival. Schalke, which finished second last year, endured its worst season since it was relegated in 1982-83.
"In the end we secured survival. That was my job, and it wasn’t easy," said interim Schalke coach Huub Stevens, who was coaxed back for his third stint for the final eight league games.
Also, Freiburg drew 1-1 at home with Fortuna Duesseldorf.