The queen is the most powerful piece on a chessboard and it is always difficult to substitute this piece. Though exchange of a queen for two rooks is considered a fair enough value, it depends on the position to get a decisive result for either side.

However, when a queen is exchanged for a bishop and rook or a rook and knight, a win is a foregone conclusion in most cases. However the queen needs to be moved with accuracy to bring about a win.

In the game which follows, Black is forced to part with his queen after White under promotes one of his pawns into a knight. The white queen then mops up the pawns on the board and easily decides the game in White's facour.

White: Furman Abramovich  - Black: Paul Keres, Moscow , 1948, Queen's Indian Defence
1.d4 Nf6 2.c4 e6 3.Nf3 b6
The Queen's Indian Defence where the bishop is fianchettoed on the queen side.
4.g3
White in turn fianchettoes his bishop on the King side
4. ..Ba6 5.Qa4
The queen moves out in t0oplay rather early
5. ..c6 6.Nc3 d5 7.cxd5 exd5 8.Ne5 Bb7
If 8...Qc7 9.Bf4 and if 8...Qc8 9.Bg5
9.Bg5 Be7 10.Bg2 0–0 11.0–0 h6
Trying to push back the bishop when a better move would have been 11...Nfd7
12.Bxf6 Bxf6 13.f4 a5
He could have also tried out 13...b5
14.Rad1 Qc8 15.e4
Good move! White gets an opportunity to advance this backward pawn
15. .. b5
Black now decides to focus on the queen side and pushes the queen back
16.Qc2 Na6 17.Rc1
Changing files. If 17.exd5 Nb4 18.dxc6 gives advantage to White
17...Nc7 18.Rfd1 Qe6 19.Nxd5
Sacrificing the knight! If 19.exd5 cxd5
19...Nxd5
If 19...cxd5 20.Qxc7 with advantage for White  
20.exd5 cxd5 21.Qc7
Immediately moving onto the 7th rank
21. ..Ra7
More or less a forced move. If 21...Rfb8 22.Nd7 Bd8
22.Qc5 Ra6 23.Qxb5 Rb6 24.Qe2 Be7 25.Rc2 Rd8 26.Qh5
Suddenly shifting flanks
26. ..Bd6 27.Bh3 Qf6
Not the right move. He could have played   27...Qe7 28.Re2 Bxe5
28.Ng4
A better continuation was 28.Nd7 Rxd7 29.Bxd7 Qe7 30.Ba4 Qe3+ 31.Kg2
28...Qe7 29.Re2 Qf8
If 29...Qxe2 30.Nxh6+
30.Ne5 Ba6 31.Rf2 Bb5 32.Rc1 Bb8 33.Rfc2
Doubling dangerously
33. ..g6 34.Qh4 Kg7 35.a3
Now white has numerous threats at his disposal like 36.Rc8 or  36.Nf7 even 36.NIf g4 [35.Rc8 Rxc8 36.Rxc8 Qb4]
35...Bxe5 He decides to give up the bishop pair advantage to eliminate the dangerous knight
36.fxe5 Bd3 37.Rc6
Inviting an exchange. If  37.Rc8 g5
37...Rxb2 38.Qf6+ Kg8 39.e6
Firing on all cylinders
39. ..Rdb8 40.Rc8
A better continuation which would have led to victory was 40.e7 Qe8 41.Rc8 Rxc8 42.Rxc8 Rb1+ 43.Kf2 Rf1+ (43...Rb2+ 44.Ke3) 44.Ke3 Rxf6 45.Rxe8+ Kh7 46.Rh8+ Kxh8 47.e8Q+
40...Rxc8 41.Rxc8 Rb1+ 42.Kf2 Qxc8 43.exf7+ Kh7 44.f8N+
Under promotion! White does not take a queen but instead opts for   a knight as this lands the King in a check immediately. If 44.Bxc8 Rf1+
44...Kg8 45.Be6+
Diagram 1
45. ..Qxe6
Black has to part with his queen to save the king
46.Qxe6+ Kxf8 47.Qxd5 Bf5 48.Qxa5 The queen has gobbled pawn at will and has no compensation as a rook and bishop against a queen is not match
48.   ..Kf7 49.a4 Ke6 50.Qe5+ Kd7 51.g4 Rb2+ 52.Kg3 Rb3+ 53.Kf4 If 53.Kh4 g5+ 54.Kh5 Rh3 checkmate
53...Be6 54.Qg7+ Kd6 55.Qf8+ Kd7 56.Qxh6 and Black resigned.
Diagram 2
Black to play and win
1. ..Rxe3  2.fxe3 Qxg3+  3.Bg2 Nxe3 and it is all over for White.