Winsome Threesome

AM playing in the U171 section of the Bradford Congress, which started this evening upstairs at the city's Latvian club.
There was an oddity on the top three boards when the lower-graded player in each case offered a draw.
In two of the games he was ahead on material; in the third he had a big, but unclear, attack.
The draw offers were accepted on boards one and three, where there were material deficits, which at least meant the higher-graded players did not start with a duck.
On board two, the offer was declined (by me). Three moves later, I had a completely lost position (a tad over -5, according to Stockfish10).
But my opponent failed to find the winning combination, and eventually I had the rare satisfaction of delivering mate.

Black has just played 41...Qf2-e2

*****
*****
*****
*****
*****
Black was lost in any event, eg 41...Qg3 42.f6.
42.Rxd6+ Ke7
Or 42...Bxd6 43.Qxd6+ Ke8 44.Bc6#
43.Qc7+
Or 43.f6+ Ke8 44.Qc8+ Rxc8 45.bxc8=Q#
43...Kf8 44.Qxb8+ Kg7 45.f6#