Barcelona made a disappointing start to their Champions League campaign by losing 2-1 to Monaco after suffering an early blow from Eric García’s dismissal.

García was shown a straight red card 11 minutes in for a foul on Monaco’s Takumi Minamino, who was clear in front of goal after a misplaced pass from Marc-André ter Stegen, the visitors’ goalkeeper.

The hosts grabbed the lead five minutes later when Maghnes Akliouche struck a low shot into the net, but Lamine Yamal equalised in the 28th minute by finishing from the edge of the penalty area.

Monaco kept pushing and got their reward in the 71st minute when the 18-year-old substitute George Ilenikhena fired past Ter Stegen to secure victory in their first main stage appearance in five years in Europe’s elite club competition.

“We didn’t understand each other in that moment, I feel bad for Eric,” Ter Stegen told Movistar Plus of García’s red card. “We played 80 minutes with one less. It’s a football thing. The defeat hurts, because with 10 men on the pitch we gave our all and tried to get a point.”

Bayer Leverkusen opened their Champions League campaign with a resounding 4-0 win at Feyenoord, running riot in the first half. Florian Wirtz scored two, while Alejandro Grimaldo also got on the scoresheet and there was an own goal from the Feyenoord goalkeeper Timon Wellenreuther, with the home side jeered off the pitch at half-time by their own supporters.

Leverkusen were ahead in the opening five minutes as Wirtz took advantage of a defensive slip by Ramiz Zerrouki. Jeremie Frimpong then set up the next two goals with his strong running down the right flank. The first was for Grimaldo in the 30th minute with some help from a clever no-look pass by Victor Boniface and the next a precision cross to the back post to find Wirtz flying in to convert unchallenged in the 36th minute.

Leverkusen went four up on the stroke of half-time. A free-kick found the centre-back Edmond Tapsoba at the back post as his header back into the danger zone struck Wellenreuther on the foot and ricocheted slowly backwards over the line for an own goal.

While the home side showed more spirit and energy in the second half, they rarely threatened to score. Leverkusen went close to a fifth goal as the match went into stoppage time, with David Hancko clearing off the line from Aleix García.

A late header by the defender José María Giménez gave Atlético Madrid a 2-1 win over RB Leipzig, despite the visitors taking a shock lead in the fourth minute thanks to a header by Benjamin Sesko after a quick counterattack.

Antoine Griezmann struck a fine volley into the top corner in the 28th minute to level and Atlético dominated, with 20 attempts on goal, though they had to wait until the 90th minute to find the winner, with Giménez heading in a cross from Griezmann.

Brest won their first ever match in a European competition, after goals from Hugo Magnetti and Abdallah Sima secured a 2-1 victory over Sturm Graz in Brittany.

Magnetti scored Brest’s maiden European goal in the 23rd minute, expertly controlling the ball on his chest before volleying into the bottom corner to break the deadlock. However, Sturm Graz equalised just before half-time when Brest’s Edimilson Fernandes inadvertently sent the ball into his own net.

Brest adopted a more aggressive approach following the interval and they were rewarded when Sima restored the French side’s advantage by skilfully evading his marker and scoring with his left foot in the 56th minute. As the match neared its end, Sturm Graz were reduced to 10 men when Dimitri Lavalée received his second booking after a tackle on Magnetti.

Elsewhere, a fortunate goal from the winger Kerem Akturkoglu and a superb free-kick by his Turkish compatriot Orkun Kökçü earned Benfica a 2-1 victory at Red Star Belgrade.

Akturkoglu opened the scoring for the Portuguese side in the ninth minute, converting a cross at the far post from close range. Kökçü then doubled the advantage a minute before the half-hour mark with a meticulously placed free-kick from 25 yards, finding the net just inside the top right corner.

Red Star reduced the deficit when Felício Milson was played through and scored from close range four minutes before time, but they were unable to find an equaliser.