Nigerian Victor Boniface made history on Tuesday night by scoring his first UEFA Champions League goal in Bayer Leverkusen's tight 1-0 victory over AC Milan.
The 23-year-old's shot from close range proved decisive as Milan's frustration grew with missed opportunities, including a miss by Alvaro Morata and a rebound off the crossbar.
This defeat follows Milan's 3-1 loss to Liverpool in their first match, despite winning three consecutive Serie A matches, including the Milan Derby.
Leverkusen, who achieved a Bundesliga and German Cup double last season, continue to be in good form.
Xabi Alonso's side previously won 4-0 against Feyenoord in the Champions League and drew 1-1 with Bayern Munich last weekend in the Bundesliga.
Other results
Elsewhere, Arsenal achieved their first victory in the Champions League this season, defeating Paris Saint-Germain 2-0 at the Emirates Stadium.
First-half goals from Kai Havertz and Bukayo Saka enabled the Gunners to claim a crucial victory over the French giants.
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This victory places Arsenal with four points in the league phase, after their first draw against Atalanta.
Despite playing away from home, Manchester City dominated Slovan Bratislava 4-0, with Phil Foden scoring his first goal of the season and Erling Haaland also scoring.
great victories
Also on Tuesday, Robert Lewandowski's brace led Barcelona to a resounding 5-0 victory over Young Boys.
Raphinha and Íñigo Martínez increased the score before the break, and Lewandowski's second goal sealed the victory.
Barcelona's resounding victory follows their disappointing defeat against Monaco.
They are now looking forward to a high-level clash against Bayern Munich on matchday three.
READ ALSO: Boniface shines on Champions League debut as Leverkusen thrash Feyenoord 4-0
Meanwhile, Young Boys will face a free-flowing Inter side, having conceded eight unanswered goals in their first two matches.
Inter were ruthless at their own game, defeating FK Crvena Zvezda 4-0
Borussia Dortmund recorded the biggest win of the night with their 7-1 annihilation of Celtic with Kareem Adeyemi bagging a brace in the one-sided encounter.
With these results, the Champions League qualification begins to take shape, setting the stage for exciting clashes in the coming weeks.