From the Wanda Metropolitano - Liverpool may be European, world and soon-to-be English champions, but if there's one team you don't want to concede an early goal to it's still Diego Simeone's Atletico Madrid, as they proved in a frustrating night for the Reds on their return to the Spanish capital. 

The impressive first-leg win for Atleti, somewhat surprisingly, marked the first time Jurgen Klopp and Simeone - perhaps the two most important managers in the last decade of the Champions League (bar Zinedine Zidane) - have come up against one another in a competitive outing. 

In the preceding weeks and months, the narrative had been on Klopp, the former nearly-man turned master of the universe, and Simeone - contrasting to the German tactically but his contemporary in taking a sleeping giant to the fringes of greatness - in his supposed demise. 

Saul Niguez

However, Tuesday night proved there is life left in Simeone, while Klopp still has worlds to conquer.

​Nostalgia was the order of the day for the visitors on their return to the Wanda Metropolitano eight months on from one of their great modern triumphs, but the opening goal was a stark and unwelcome reminder of one of their former frailties - set pieces.

Koke's fourth-minute corner was poked home by Atleti's prince of big goals Saul, after Roberto Firmino failed to clear his lines and thus the tone for the match was set. In a way, it was oddly reminiscent of the Champions League final, only with Liverpool in the Tottenham role this time.

Klopp fielded Liverpool's strongest lineup - weirdly the first time he has done so this season - but things just didn't click for the Reds, while Atleti - whose eyebrow-raising starting XI featured forgotten man Thomas Lemar - relished the occasion.

The hosts, whose stadium has so far arguably given more joy to Liverpool than their own fans, snapped into tackles and pressed from the front, with Alvaro Morata forcing Alisson into a save to prevent it from being 2-0 before the 20-minute mark.

Atletico Madrid v Liverpool FC - UEFA Champions League Round of 16: First Leg

The home crowd crackled like crossed wires at the vintage Simeone display, with every forced pass backwards cheered like a goal and periods of Liverpool possession greeted with ear-drum bothering whistles.

While this game was another (albeit important one) in Liverpool's packed calendar, there was a sense, transmitted from the electricity of the crowd to the players, that the here and now was all that mattered for Atleti - whose own domestic ambitions have long since gone.

If Simeone is going this summer, he'll go down fighting. Sat deep. With two banks of four. Gleefully accepting just 25% of the possession. He has still never lost a Champions League knockout encounter at home.

​Liverpool, meanwhile, look just a little different in Europe away this season. Less thrusting, less relentless, but more vulnerable. Everything on the night looked a little off, every skid of the ball, every Trent Alexander-Arnold cross, every Mohamed Salah turn, every Roberto Firmino jink an armpit hair's breadth off. 

The Reds haven't always been blisteringly good this season but they have always capitalised on errors and produced enough moments of wonder to eke out (almost) every win. At the Wanda, for the first time, they looked a little tired, uncomfortable and bruised - Jordan Henderson's apparent hamstring injury the most worrying takeaway from the game - and, thus, were unable to force the opportunity against the immovable opponent.

Generally speaking, goals come from mistakes and ​Atleti - compact and not so much street smart but card-carrying Mensa members of 'street' with a doctorate from Oxford - simply don't make mistakes at home in Europe.

An interception and lung-busting 30-yard run from Marcos Llorente late in the second half drew cheers from the crowd as if it were a match-winning goal, while the reaction to the introduction of Diego Costa with 15 minutes to go would've come close to rivalling any of the sounds from the Liverpool fans in the same ground last June. By the end, Liverpool were a little fortunate not to concede a second as Atleti harried and bullied on the counter.

​The Reds return to league action knowing what they need to do in the second leg on 11 March. The task is not insurmountable (they know that from last season). Atleti too know how fragile a first-leg lead can be.

Jurgen Klopp

Pre-game Klopp described Liverpool as feeling not like winners but just another team who wants to win it this year. With the ​Premier League all but wrapped up, they'll have to show that at Anfield in three weeks' time.

Simeone has already proven his and Atleti's hunger is still very much there.