1. f6 Db3 2. f7!! Dd1+ 3. Kh6 Df3 4. Kg7 Dg4+ 5. Kh8 Df5 6. Kg7 Dg5+ 7. Kh7 Df6 8. Kg8 Dg6+ 9. Kf8! Ka4
10. Ke7 Dg7 11. Ke8 De5+ 12. Kd7 Df6 13. Ke8 De6+ 14. Kf8 Kb3
15. Kg7! De7 16. Kg8 Dg5+ 17. Kh8 Df6+ 18. Kg8 Dg6+ 19. Kf8 Kb2
20. Ke7 Dg7! 21. Ke8 De5+ 22. Kd8 Df6+ 23. Ke8 De6+ 24. Kf8 Kc1
25. Kg7 De7 26. Kg8 Dg5+ 27. Kh8 Dh6+ 28. Kg8 Dg6+ 29. Kf8 Kd1
30. Ke7 Dg7 31. Ke8 De5+ 32. Kd7 Df6 33. Ke8 De6+ 34. Kf8 Ke2
35. Kg7 De7 36. Kg8 Dg5+ 37. Kh8 Df6+ 38. Kg8 Dg6+ 39. Kf8 Kf3
40. Ke7 Dg7 41. Ke8 De5+ 42. Kd7 Df6 43. Ke8 De6+ 44. Kf8 Kf4
45. Kg7 De7 46. Kg8 Dg5+ 47. Kh7 Df6 48. Kg8 Dg6+ 49. Kf8 Ke5
50. Ke7 Dd6+ 51. Ke8 Ke6! and now the only move to complete the 100-ply count is 52. Sc2! 1/2-1/2

Other lines:

2. Kh6? Dd1! 3. f7 Df3 4. Kg7 Dg4+ 5. Kh8 Df5 6. Kg7 Dg5+ 7. Kh7 Df6 8. Kg8 Dg6+ 9. Kf8 Ka4 10. Ke7 Dg7 11. Ke8 De5+ 12. Kd7 Df6 13. Ke8 De6+ 14. Kf8 Kb3 15. Kg7 De7 16. Kg8 Dg5+ 17. Kh8 Df6+ 18. Kg8 Dg6+ 19. Kf8 Kb2 20. Ke7 Dg7 21. Ke8 De5+ 22. Kd8 Df6+ 23. Ke8 De6+ 24. Kf8 Kc1 25. Kg7 De7 26. Kg8 Dg5+ 27. Kh8 Df6+ 28. Kg8 Dg6+ 29. Kf8 Kd1 30. Ke7 Dg7 31. Ke8 De5+ 32. Kd7 Df6 33. Ke8 De6+ 34. Kf8 Ke2 35. Kg7 De7 36. Kg8 Dg5+ 37. Kh8 Df6+ 38. Kg8 Dg6+ 39. Kf8 Kf3 40. Ke7 Dg7 41. Ke8 De5+ 42. Kd7 Df6 43. Ke8 De6+ 44. Kf8 Kf4 45. Kg7 De7 46. Kg8 Dg5+ 47. Kh7 Df6 48. Kg8 Dg6+ 49. Kf8 Ke5 50. Ke7 Dg7 51. Ke8 Ke6 52. Kd8 Dxf7 0-1

9. Kh8? Dxf7! 10. Sc2 dxc2

15. Kg8? Kb2!

20. ... Dh7? 21. Kf6! delaying

No faster are:
50. ... Dg7 51. Ke8 Ke6 52. Kd8 1/2-1/2
50. ... De6+ 51. Kf8 Kf6 52. Kg8 1/2-1/2

This is based around a known endgame KPKQ where wPf7 cannot be captured by bQ because it stalemates wKh8. However here White always has the losing move Sc2, so has not got the stalemate recourse.

White still must spend first 3 moves pushing Pf5 to f7 & K to h6. bQ can check on his 2nd move, so White can't just promote in 3 moves. White threatens at any point to promote, and which point Black no longer wins. Now bK is a long way from the action. Black strategy is to repeatedly chase wK to f8 in a 4 move sequence, at which point it is safe for bK to take a step closer. White must also avoid leaving Pf7 pinned, or letting bQ move to f8 safely.

There is a little flexibility in the moves, as the example solution shows. In particular, White on moves 5n+2 can move to the 7th or 8th row.

However the timing is very close. In order to claim the draw under 50 move rule, White must have moved 1. f6!, 2. f7! & 3. Kh6 to get the pawn moves over and done with. So the dual elimination happens 50 moves later!