With the Champions League group stage in full swing, theScore examines 10 takeaways from Europe's preeminent club football competition.
On the way to reaching a Champions League final last season, Tottenham shockingly led for just 173 minutes of their 13 continental clashes. On Wednesday in Greece against Olympiacos, Spurs held a two-goal advantage for all of 24 minutes before throwing it away in a 2-2 draw.
It was a deserved result for an Olympiacos side boosted by bright individual performances from Mathieu Valbuena and Daniel Podence, but for Spurs, it was a sloppy display exemplified by Christian Eriksen, who lost possession 22 times. Consider Tottenham mired in a secret slump with just five wins in their last 19 in all competitions.
Barcelona might have left the Westfalenstadion on Tuesday with a defeat had Marc-Andre ter Stegen not stopped Marco Reus' second-half penalty. That's now four of six penalties saved by Ter Stegen in the Champions League, joint-most since detailed data was first collected in 2003-04.
It was one of several stellar saves on a day with excellent efforts in net. In Naples, Alex Meret rebuffed Mohamed Salah with what was Liverpool's best chance of the match, a denial that was second-best to Adrian's acrobatic stop to thwart Dries Mertens. Ajax's Andre Onana, Leipzig's Peter Gulacsi, and Valencia's Jasper Cillesen all had standout showings as well.
Club legend Frank Lampard's spell as Chelsea boss has been a mercurial stretch amplified by bizarre home form. Including Tuesday's 1-0 defeat at Stamford Bridge against Valencia, Chelsea have failed to win any of their three home matches in all competitions.
Had Ross Barkley not fired his late penalty into the ionosphere, it would have been three draws for Lampard and Co. to go with stalemates against Leicester City and Sheffield United. Against both the Foxes and Blades, Chelsea wasted leads to settle for one point. Baby steps at home for a side that did not lose any of its 15 Europa League matches last season.
Atletico Madrid have been a menace at home under Diego Simeone. Against Juventus, they conceded twice at their own ground for just the third time in European competition. The Old Lady join Benfica and Chelsea as the only clubs to achieve that feat, and are one of nine to score away against Atletico in 31 tries.
Still, Juventus could not get a result after debutant Hector Herrera's late set-piece goal gave the hosts two tallies from dead ball situations, something that will irk Maurizio Sarri. Of note, Atletico goalkeeper Jan Oblak has conceded two goals in three successive matches for club and country (Israel, Real Sociedad, Juventus) for the first time since he was a 19-year-old at Rio Ave. in 2012.
It was always going to prove difficult to replace generational talents like Matthijs de Ligt and Frenkie de Jong, though Ajax look like a side who haven't skipped a beat thanks to the performances of some newcomers in Tuesday's commanding 3-0 victory over Lille.
Versatile duo Lisandro Martinez and Edson Alvarez starred in the midfield, particularly the latter, who was tidy with 91% pass completion. Somewhere, Ronald de Boer was choking on humble pie. Reserve team grad and USMNT member Sergino Dest also made a good account of himself at right-back, and Quincy Promes set the tone in bagging the opener.
Nasser Al-Khelaifi's Qatari-backed attempts to turn Paris Saint-Germain into the French version of Real Madrid's famed Galacticos - and, in turn, capture continental silverware - hasn't quite gone to plan. On Wednesday in the French capital, it was the club's support staff that embarrassed Los Blancos.
With Neymar, Kylian Mbappe, and Edinson Cavani all out, Angel Di Maria starred against his former side with a first-half brace, but it was former Everton bulwark Idrissa Gueye who was perhaps best on the day. The Senegalese midfielder completed 100% of take-ons, 93% of his passes, and chipped in with four tackles, six recoveries, two interceptions, and an assist.
Were it not for Tomas Soucek's daft foul and Inter's subsequent 92nd-minute equalizer from a Stefano Sensi free-kick, Slavia Prague would have pulled off a group stage shocker at the San Siro on Tuesday. The Czech champs and three-time European Cup winners eventually shared the spoils in a 1-1 draw.
Peter Olayinka scored for Slavia 18 minutes after the break when a lunging save from Samir Handanovic rebounded directly into the striker's path. It was the highlight of a stretch of pressure from the visitors that was contrary to the usual approach of continental minnows away from home. Full credit to their enterprising efforts.
The Champions League provides a platform where budding talents transform into veritable stars under the floodlights of evening football. RB Salzburg's Erling Braut Haaland has the looks of a future footballing deity after the 19-year-old Norwegian guided his side to a 6-2 win over Genk on Tuesday.
Best known for his father (Alf-Inge Haaland was the recipient of the famous Roy Keane leg break tackle) and a nine-goal performance against Honduras in the U-20 World Cup, Haaland was irrepressible. He devoured the pitch with deceiving pace and potted goals with relative ease to become the first teen to record a first-half treble in tournament history.
Atalanta owes much of their club-best third-place domestic finish and maiden spot in the Champions League to an attacking style built around Duvan Zapata, Papu Gomez, and Josip Ilicic, who all helped La Dea record a Serie A-high 77 goals last season.
On Wednesday in Croatia, manager Gian Piero Gasperini's attacking style was exposed by Dinamo Zagreb. Behind Mislav Orsic's hat-trick, rapid passing, and speedy wide attacks, Dinamo raced to a 4-0 victory that could have been far worse for Atalanta had the hosts been more clinical. It was just the second win in 25 Champions League group stage matches for Dinamo.
In the 62nd minute of Tuesday's visit from holders Liverpool, Napoli center-back Kalidou Koulibaly lunged to dispossess a surging Roberto Firmino before sprinting downfield to spearhead an attack that Dries Mertens wasted with a poorly weighted ball.
It was a fitting example of a tireless player whose exploits set the tone for the Partenopei. Koulibaly led the way against the Reds' lethal three-pronged attack with a pair of tackles, two interceptions, five clearances, and 80% passing accuracy on 70 touches. Only his opponent at the Stadio Sao Paolo, Virgil Van Dijk, can match Koulibaly's continued excellence in central defense.