The South Korean netted his first ever brace in Europe's elite competition to keep the Werkself not just top of Group C, but firmly on course to join Bundesliga roommates Borussia Dortmund in the knockout rounds to boot.
'A world-class player'
"Son's a very good friend of mine," Leverkusen goalkeeper Bernd Leno told uefa.com after the game. "I'm very happy for him as he scored both our goals. He's a good guy and he has also proved today in the Champions League that he's a world-class player."
Bayer were made to work hard for their third successive win in the competition, but when the chances finally came, Son's clinical eye for goal made all the difference. The 22-year-old former Hamburger SV attacker's first strike left Zenit goalkeeper Yuriy Lodygin with no chance, while his second capped a move typical of Leverkusen's counter-attacking bent.
'The whole team is the hero'
"There have been many [career highlights], but it was certainly something special to score my first double in the Champions League," admitted Son. "[Zenit] are very strong at home, but we showed that we are a good team and that we can be successful. I don't think I'm the hero, the whole team is the hero."
As long as Roger Schmidt's side avoid defeat at home to AS Monaco in three weeks' time, they'll be through to the last 16 with a game to spare. Victory would even see them finish top of the group and, in theory, result in a more favourable draw. Although with Son in this kind of form, it's the rest of the competition that should be worried.