Calamity

IN the second of today's double-round games, I faced a 10-year-old Ukrainian boy.

White has just played 45.Rc2-b2 in Andril Tsiapko (1369) - Spanton (1934), Benidorm U2000 Round 7

While I was thinking about my reply, White offered his third draw of the game - the second offer made while my clock was running.
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45...f5??
I should have accepted that the position was dead-drawn. After the text, it is lost for Black.
46.Nd3
Threatening a fork on e5.
46...Kf6 47.Ne5 Be8 48.gxf5 Rh1 49.Ng4+ (1-0, 62 moves)