He how has 39 goals in 33 matches across competitions this season.
For Chelsea, it was a night to forget. Marcos Alonso was sent off as well.
Bayern script UCL history, Gnabry's London delight continues
Chelsea have now faced eight home defeats in all competitions this season.
Bayern are only the third team in UCL history to win their first seven games in a season.
This was Bayern's seventh win on English soil in the Champions League.
Gnabry has now scored all six of his Champions League goals in London.
Key numbers from the Napoli-Barcelona encounter
Barcelona have progressed from each of their last 19 knockout ties in the Champions League when they have avoided defeat away from home in the first leg.
The Spanish giants have only won one of their previous nine away games in the Champions League knockout stage.
Napoli striker Dries Mertens has scored six goals in the Champions League this season.
Lewandowski's fine run continues
Lewandowski has scored nine away UCL goals this season. This is now a joint record in a single season in the competition along with Cristiano Ronaldo in 2013-14. He has also been involved 13 goals in just six Champions League appearances this season.
A look at the results
⏰ RESULTS ⏰
⚽ Mertens Griezmann net as Napoli hold Barcelona 🔴 Gnabry (2) Lewandowski inspire Bayern in London