AS Monaco 2-1 FC Barcelona
FC Barcelona were unable to transfer their LaLiga form to the UEFA Champions League after a 2-1 loss to AS Monaco on Thursday.
The absence of Dani Olmo through injury in the weekend win at Girona prompted Barca to a change and Eric Garcia were tasked to replace the late off-season signing.
Garcia unfortunately wouldn't last the whole game and got a straight red card on ten minutes for bringing down Takumi Minamino on the edge of the area.
The reduced numbers didn't help as six minutes later Maghnes Akliouche burst through on goal and fired past a static Marc-Andre Ter Stegen.
Fortunately, Barca were back on even terms when Lamine Yamal continued his fine form and fired in the bottom-corner from a low pass ahead of the half-hour mark.
Given the even set of affairs thereafter, Monaco regained the lead late on when George Ilenikhena broke in-behind the defence with pace to fire beyond Ter Stegen and secured victory.
Atalanta 0-0 Arsenal
Arsenal started their campaign in the Champions League with a tense goalless draw at Serie A outfit Atalanta in Bergamo.
The Gunners named Declan Rice back in the starting fold after missing Sunday's win over Tottenham Hotspur through suspension and replaced Jorginho, with Gabriel Jesus back in for Leandro Trossard.
Both teams couldn't find the back of the net in a rather quiet first half which ended goalless, but matters lighted up after the interval.
This as the home side were given a penalty when Ederson stormed into the area to get a sight on goal only to be brought down by Thomas Partey.
From the subsequent penalty, Italian international Mateo Retegui decided to step up but couldn't hit the net as goalkeeper David Raya guessed correctly and smothered him.
Feyenoord 0-4 Bayer Leverkusen
German champions Bayer Leverkusen showed Eredivisie boys Feyenoord no mercy and cruised to a commanding 4-0 victory at De Kuip in Rotterdam.
Leverkusen, who stormed to the Bundesliga title in unbeaten fashion last season, took the lead on five minutes when Florian Wirtz finished off from the area to open his account in the tournament.
More came well on the half-hour mark as Alex Grimaldo popped up at the back-post of the danger area and finished off with ease – leaving Feyenoord on the back-foot.
There were no slowing down from Xabi Alonso's boys, who nabbed a third after six minutes where Wirtz had the presence of mind to volley in a cutback and completed his brace.
Feyenoord's evening just continued to get worse on the half-hour mark as goalkeeper Timon Wellenreuther helped a scrambled effort past his own net after attempting a clearance.
No goals were added in the second stanza, seeing last season's Europa League finalists claim a commanding victory in their tournament opener.
Atletico Madrid 2-1 RB Leipzig
Atletico Madrid came from a goal down to get past RB Leipzig 2-1 and made a winning start to this season's tournament.
Julian Alvarez, Angel Correa, and Rodrigo Riquelme all came in for the host from their league victory over Valencia at the weekend.
Leipizig made a powerful start on just four minutes with Benjamin Sesko on hand to head in a rebound following a loose ball from goalkeeper Jan Oblak.
Atleti were level later on in the first half when Antoine Griezmann volleyed in a fine delivery from Marcos Llorente before Juan Gimenez turned it around at the death to head in the winner.