English teenager Jude Bellingham shone for Borussia Dortmund as he opened the scoring in German side's Champions League Group C victory at Besiktas.
The 18-year-old midfielder chested Thomas Meunier's lofted ball into his path before firing through keeper Ersin Destanoglu's legs from a tight angle.
A smart run from Bellingham then teed up Erling Braut Haaland to double Dortmund's lead before the break.
Javi Montero's late header for the hosts then set up a nervy finish.
Haaland's strike was his 21st goal in 17 games in the Champions League across spells with Red Bull Salzburg and now Dortmund.
The 21-year-old, who is the youngest player to reach that total, has also achieved the feat in 10 games fewer than any other player - Ruud van Nistelrooy being the next closest in 27 games.
Haaland, who has scored 66 goals in as many games for Dortmund, earlier missed a great chance to double the visitors' lead while Bellingham almost added his second after another jinking run.
On-loan Chelsea striker Michy Batshuayi was also denied at the other end by Dortmund goalkeeper Gregor Kobel after going through for the hosts.
In Wednesday's other early kick-off, Sheriff Tiraspol got their first Champions League campaign off to a flying start as they beat Shakhtar Donetsk 2-0 at home in Group D.
Goals from Adama Traore and substitute Momo Yansane meant the Moldovan club become the first debutants to win their opening group match in the competition since Leicester City in 2016.