The Hammers had defended heroically for 83 minutes before goalkeeper Lukasz Fabianski was finally beaten by substitute Jonas Hoffman.

A one-goal deficit might have given David Moyes' side hope going into next week's second leg at the London Stadium, despite facing a side unbeaten all season.

But disaster struck in stoppage time when a second substitute, Victor Boniface, headed home Hofmann's cross, to leave West Ham's hopes of a third consecutive European semi-final looking horribly slim.

A yellow card for Lucas Paqueta, ruling the Brazil international out of the second leg, only adds to the task facing the east Londoners.

The Hammers, without injured top scorer Jarrod Bowen and defensive midfield linchpin Edson Alvarez through suspension, were almost undone in the seventh minute when Josip Stanisic's wayward shot was flicked towards goal by Patrik Schick but the ball went straight to Fabianski.

But Leverkusen were given a warning of West Ham's prowess on the counter-attack moments later when Michail Antonio outstripped Jonathan Tah on the left wing and produced the best chance of the first half.

The burly frontman squared the ball to Mohammed Kudus, but the Ghana winger's first-time strike was comfortably held by Matej Kovar.

However, West Ham were largely camped in their own penalty area and Fabianski palmed away Jeremie Frimpong's curler before Exequiel Palacios's drive was deflected over.

Paqueta's over-enthusiastic challenge on Amine Adli earned him his booking - the Brazilian survived a red card check - and provoked a mild skirmish on the touchline.

Fabianski might have suspected he was in for a busy evening and he was proved right, making big saves to keep out dangerous efforts from Alejandro Grimaldo, Shick and Edmond Tapsoba.

Early in the second half Emerson Palmieri was shown a yellow card after catching Adli on the ankle, meaning the left-back will also sit out next week's return leg.

Frimpong, a former Manchester City youngster, hit a low angled drive straight at Fabianski, before the 38-year-old Pole made a stunning save to tip Shick's instinctive header over the crossbar.

But with seven minutes remaining Fabianski was powerless to prevent Hoffman's shot bouncing through a sea of white shirts and into the net after a corner was only half-cleared.

Tomas Soucek cleared two Tah efforts off the line in a desperate finale before Boniface headed the second to leave the Hammers devastated.

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