Normal opening, Black is playing a bit more defensive / solid than White.
Black plays tengen and claims a big moyo.
White goes for territory on the left side and Black for a large centre moyo.
White reduction feels like an overplay.
The Black tenuki (39) gives White an opportunity to start building something in the centre …
but White answers with a pincer (40) after which black walks into the centre (41).
40 is a big move, but sometimes big moves are not enough.
The series 27-41 was decisive.
White discovers that Black’s thickness in the centre makes it very difficult to create a living group there. White struggles for a few dozen more moves and resigns.
Instead of White K3 (40) he should have walked out of the centre and secure his stones.