Mark Flekken admitted he was left “speechless” after Bayer Leverkusen failed to hold onto their lead in a dramatic 3-3 draw with Heidenheim on Saturday.

With the top-four race heating up in the Bundesliga, Leverkusen's hopes of finishing in the Champions League places took a major blow as they were twice pegged back by the league's bottom side.

Malik Tillman and Patrik Schick gave Leverkusen an early 2-0 advantage, but Heidenheim responded after the break, with Hennes Behren's cross-shot pulling one back.

Marvin Pieringer levelled the score from the penalty spot and then powered home a corner to snatch a point after Schick had restored Leverkusen's lead.

The Werkself remain sixth in the Bundesliga table, but are four points behind Stuttgart, who could extend that lead to seven points for the international break if they beat Augsburg on Sunday.

Leverkusen are now winless in their last three league matches, drawing all three, and Flekken, who has just returned from injury, lamented the team's lack of concentration.

"We talked at half-time about not being able to get complacent," Flekken told DAZN.

"I'm a bit speechless."

Leverkusen are now given just a 30.2% chance of finishing in the top four, according to the Opta supercomputer, with their most likely finishing position currently sixth (40.6%).

Heidenheim suffered their heaviest Bundesliga defeat in the reverse fixture in Leverkusen (0-6).

They remain winless in their last 14 top-flight matches, their longest winless streak in the competition (since at least 2004-05), but head coach Frank Schmidt used the last meeting with Leverkusen as motivation.

"You don't forget something like that, you don't want to experience something like that a second time," he told Sky Sport.