fredthebear: In the final position...Black is down a pawn, but can easily force the draw by giving a series of checks after promoting the a-pawn to a new Black queen.
Try to visualize this sequence...The Black pawn will queen first, followed immediately by the White pawn promoting to queen. (61...a1=Q 62.g8=Q)
THE NEW BLACK QUEEN MUST CHECK CONTINUOUSLY AND NEVER GIVE THE NEW WHITE QUEEN A CHANCE TO MOVE!
After the pawn promotions, the new Black queen will then mercilessly check the White king as many times as necessary, perhaps repeatedly until a draw by perpetual check. It would be a senseless waste of time to continue such a game of numerous checks.
Or, if the White king moved to Kf7 or Kh7, an exchange of queens can be forced. The Black queen will check so that Kg7 occurs. Then a skewer check on the g-file will lead to an exchange of queens: Black queen takes White queen QxQg8, and White king re-takes KxQg8.
After both queens are off the board, the Black king captures the last White pawn and the game is a forced draw by insufficient mating material. King vs King is a draw by rule; it's illegal for either king to attack the other king.
(There is a winning possibility for Black should the White king wander off aimlessly. If the White king is getting checked repeatedly and steps on the light squared diagonal at Kd5 or Kc4, it would allow the Black Qa2+ skewer and the White queen gets captured next. The same blunder could occur on the g-file if the White king wonders to Kg5, Kg4 or Kg3 when Black's Qg1+ skewers the White Qg8.)
So, if both new queens are traded off, it'll be a draw. However, if the White king wanders off to Kd5, Kc4, Kg5, Kg4, or Kg3, an alert Black queen will give check and skewer the White Qg8, handing Black a winning position with the only queen left.
With proper play, a forced draw should be the result, so it's fine that the players agreed to a draw even though White had an extra pawn.