Having overturned a first-leg deficit to beat Freiburg in the previous round, West Ham boss David Moyes stated his side still had “half a chance” against treble-chasing Leverkusen.
The Hammers came flying out the blocks inside the opening quarter-hour, and their early intent was rewarded with a breakthrough in the 13th minute.
The returning Jarrod Bowen whipped a superb inswinging delivery into the six-yard box and Michail Antonio beat Leverkusen keeper Matej Kovar to the ball to head into an empty net.
Spurred on by the fervent home support, West Ham continued to look dangerous in the final third, with Bowen seeing an angled strike denied by the feet of Kovář.
The one-way traffic showed no signs of slowing down as the first half progressed, but despite further chances for Mohammed Kudus and Bowen, the visitors’ rearguard held firm to maintain their aggregate lead heading into the interval.
Clearly unimpressed by his side’s first-half display, Alonso introduced Victor Boniface and Jeremie Frimpong into the action after the restart.
Those substitutions gave Leverkusen somewhat of a foothold in the contest before the hour mark, and Frimpong came close to levelling the scores when his mishit cross was thwarted by Lukasz Fabianski at the near post.
The tie remained tantalisingly poised with time ticking into the final 20 minutes, as the hosts desperately went in pursuit of a goal to take the match into extra time.
However, it was Leverkusen who spurned a glorious chance to put the tie beyond their opponents, with Frimpong blasting wastefully over the bar when clean through.
Not to be denied, Frimpong quickly made amends in the 89th minute, as his deflected effort flew beyond a stranded Fabianski to preserve Leverkusen’s unbeaten record and set up a fascinating semi-final clash against AS Roma.
Flashscore Man of the Match: Mohammed Kudus (West Ham United)
