What was the Black mistake before move 25?

 

Did Black still had a chance before 25?

yeah. 19... Ne4?? This is a blunder to say the least.

Yea, I agree.

Had you played 19. ... g6 and then 20. ... Ne4, things would be fairly equal.

And your move 25 is a strategical mistake rather than a tactical one, because it forces a series of unwanted trades (for black).

nice play by white

17..Bxd3 is a mistake giving up your strong bishop and enabling the rook lift to h3 to the kingside attack, you should made white exch on g6 if he wants to recapturing with the f pawn and you get the f file.  As two people have commented 19..Ne4 was very bad. 

Yes, I agree with alabaster comments.

I didn't see any use for 15 ... Qc7. I thought immediate queenside expansion was necessary. Maybe a6.

I agree 17 ... Bxd3 was a mistake. You had no worries. hxg6 may look week, but it creates a very tough fortress to crack. He needs to throw pawns giving you tome to expand.

The following opening is one where Bxd3 is considered bad too.

Yes 19.. Ne4 is wrong.. asking for trouble

what about after 9.Ngf3 should black take the knight 9... Bxf3 and/or Nd7 strenghten the attack on the d5 sq ?

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 edit: I believe 9. ... Bxf3 is premature, since the white-colored bishop will be important to challenge white's d3-bishop. Nd7 seems like a mistake, since it brings the knight to a more passive position, with no clear compensation.

Thanks everyone!