3 connected passed pawns are just plain nasty and as they advanced, they should have been worth more than a piece and usually are. I really did not like 42...Qg4 and would have tried keeping my queen in the arena. My immediate (and blundering) instincts were 42..Qxa4 but such leads to a trapped knight after
43 Ra1 Qb4+ 44 QxQb4 NxQb4 45 Kc3 I would prefer either 42...Qd6 threatening f4 and controlling a3 with the thought of playing e5 later, swapping pawns and giving the knight some sort of access to e5, or 42...Qd8,
Like a week ago i read a post asking what was better 3 pawns or a piece since theoretically the value its equal. well i just finished a game where this not so common event took place. hope you find it enjoyfull.
P.S: forgive my grammar/ortographic mistakes please and look at the move list for the variants.