Liverpool's defence of their Champions League title hangs in the balance after Saul Niguez's early strike gave Atletico Madrid an aggregate lead going into the second leg of their last-16 tie at Anfield.
The Reds were given a dose of their own medicine as Atletico harried and hassled throughout, limiting them to just two clear chances and no shots on target.
Those opportunities fell to Mohamed Salah, who headed wide, and Jordan Henderson, whose hooked shot just missed Jan Oblak's far post.
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Klopp replaced Sadio Mane and Salah with Divock Origi and Alex Oxlade-Chamberlain but neither made an impact.
Two-time finalists Atletico, who have been on a poor run of form, held on to a fourth-minute lead given to them by Saul. The Spanish midfielder turned sharply to fire home after a corner came off the boot of Fabinho.
The return leg is on Wednesday, 11 March.
Liverpool attack underwhelm under pressure
Minutes before kick-off Klopp referred to Atletico having a similar "intense DNA" to his own side - and unfortunately for him they were at their intense best.
What faced the Reds was almost a mirror image - a team that relentlessly pressed and got numbers forward on the counter.
The Reds had large spells of possession in the opposition half, but Diego Simeone's Atletico side are past masters at dealing with teams of that type. They forced Liverpool into several errors when they had possession, and limited them to only two clear chances on goal.
In fact, Liverpool had to wait until the 53rd minute for their first opening - Salah's stooping header drifting comfortably wide.
The German coach, obviously not happy with his attacking threat in the first half, had twisted at half-time when he brought on Origi for the under-par Mane.
However, the Belgium striker - the hero of last year's final - was easily marshalled, bar one moment of quality when he hooked in a cross for captain Henderson, who fired wide.
Klopp's skipper came off injured in the 80th minute to cap a forgettable night.
Liverpool have it in them to turn this tie around at Anfield, but unlike Barcelona in last year's semi-final, Simeone's Atletico will be a tougher nut to crack. Klopp men's will have to be at their very best in three weeks.
