After 45 minutes of this Champions League semi-final first leg, the travelling Villarreal fans had every reason to believe they might be witnessing another miracle.

Their team had made it to half-time in the cauldron of Anfield having kept the score at 0-0, and they had also - at times - made a quadruple-chasing Liverpool look short of ideas.

As such, thoughts will no doubt have turned to the recent shock wins over Juventus and Bayern Munich, and the possibility of taking another major scalp back to Castellon.

Unfortunately, any supporter in yellow thinking along those lines had not accounted for the fact that, even among Europe's elite clubs, there are levels.

And, although Manchester City might have a strong case to be ranked alongside them, Liverpool are otherwise alone at the summit. 

It did not look much like that during an opening period that ended with the hosts having taken 12 shots, the most in a Champions League semi-final first half without scoring since such data was first collected in 2003-04.

That owed much to Villarreal's sheer refusal to offer up quality chances, with the midfield and defence working beautifully in tandem to deny all space.

The dark arts were also being deployed impressively, goalkeeper Geronimo Rulli taking as much time as he could over goal kicks, while cheap fouls were bought from frustrated opponents.

However, as he proved during Sunday's Merseyside derby win over Everton, Jurgen Klopp is never better than when given a half-time puzzle to solve.

And it looked from the very first whistle of the second period that the German had repeated the trick once again.

Suddenly, there was an extra zip to Liverpool's play, and their visitors' previously solid shape was beginning to look porous as players were dragged out against their will.

Admittedly, there was an element of fortune to the Reds' opener, Pervis Estupinan's attempted block looping over a stranded Rulli and into the back of the net.

But it had been earned through a rapid left-to-right passing exchange that opened space for Jordan Henderson to cross - the sort of move that had been missing in the first half.

From there, Liverpool smelled blood, and just two minutes later had put together another slick pattern to leave a rattled Villarreal two down. 

It was a whirlwind attacking flurry that so few teams can produce, one that will have given Klopp confidence that a third Champions League final appearance with this club awaits.

As impressive as their route to this stage of the tournament has been, Villarreal never trailed either Juventus or Bayern by more than a single goal at any stage of those ties.

And it is hard to imagine how they might close that deficit in Spain next week without opening up too much against such deadly opponents. 

Stranger things have happened, of course, but the likelihood is that a meeting with a Liverpool team eyeing the history books will prove to be a step too far for Villarreal.