Liverpool held Borussia Dortmund to a 1-1 draw in the first leg of the Europa League quarter-final as Jurgen Klopp made an emotional return to Signal Iduna Park.
Klopp guided Dortmund to back-to-back Bundesliga titles during an acclaimed seven-year spell in charge, but there was no sign of mixed emotions when he reacted with typical exuberance to Divock Origi's first-half opener.
Belgium international Origi was preferred to Daniel Sturridge in attack but he lacked the composure to add a second away goal on the stroke of half-time.
It was a miss the away side would regret as Dortmund captain Mats Hummels, back in Thomas Tuchel's line-up following a calf injury, headed a 48th-minute equaliser.
Dortmund stormed past Liverpool's Premier League counterparts Tottenham in the previous round but struggled for similar fluency as Klopp employed the relentless pressing tactics he made his trademark on this ground, leaving the tie delicately poised for when the sides meet at Anfield next week.
Both sets of fans joined in a stirring rendition of "You'll Never Walk Alone" before kick-off and there was a nervous moment for Simon Mignolet when the action got underway, the Liverpool goalkeeper dangerously cutting back across Pierre Emerick-Aubameyang when the Dortmund forward tried to charge down Mamadou Sakho's backpass.
Sakho was in the right place to block Henrikh Mkhitaryan's close-range effort in the 18th minute, before his centre-back partner Dejan Lovren headed James Milner's free-kick too close to Roman Weidenfeller and clattered into the Dortmund keeper in pursuit of the rebound.
That brought a lengthy delay, with Weidenfeller's bloodied mouth necessitating a change of jersey, after which Dortmund put their visitors under increasing pressure – only to fall behind in the 36th minute.
Milner leapt to flick on Alberto Moreno's hopeful chipped pass and Origi powered on to the loose ball before seeing a low right-footed shot clip Lukasz Piszczek's heel and nestle in the bottom-left corner.
Lovren made a vital challenge to deny Aubameyang in first-half stoppage time and Marco Reus was unable to convert when Liverpool failed to clear the resulting corner.
Origi should have doubled his tally with the final act of the half, as Moreno picked apart a Dortmund offside trap in disarray.
But his first touch took him too close to the embattled Weidenfeller, whose objections to the striker's follow-up challenge earned him a yellow card.
An apparent recurrence of his persistent heel pain ended Liverpool captain Jordan Henderson's evening at half-time, with Joe Allen introduced, while former Liverpool loanee Nuri Sahin replaced Erik Durm in the Dortmund midfield.
The hosts' equaliser came within three minutes of the restart when Hummels was allowed a free run at Mkhitaryan's right-wing cross to power a header past Mignolet.
Liverpool responded by forcing a succession of saves from Weidenfeller, who was superbly down to his right corner to keep out a powerful Philippe Coutinho strike before thwarting the Brazilian again on the rebound from Nathaniel Clyne's long-range drive.
The intensity of the match dropped, somewhat inevitably, during the final half hour and Dortmund could not craft the opportunity for a winner, as Liverpool displayed a level of defensive discipline rarely associated with their performances this season to take a draw back to Merseyside.
