In the final round of every Major, there is often a crucial point where the momentum switches away from one player and another seizes his moment.
In the 2003 Masters, that point came as the shadows began to lengthen at Augusta National and leader Len Mattiace stepped up to the final tee.
Three holes further back Mike Weir, in the final pairing, was embarking on the 15th hole, two shots behind Mattiace.
The result was a two-shot swing which helped set up a play-off - and gave Weir the momentum to take his first Major title.
Weir at hole 15
Having struggled to save par at the previous hole, Weir drives his tee shot left at the par-five 15th.
He is only just off the fairway but has a clump of trees between him and the green.
He takes an eight iron to make sure he clears the branches and lays up 100 yards from the pin in a perfect position to attack the green.
The Canadian then takes a lofted club and the ball stops dead several feet from the pin, giving him a good chance of a birdie.
There is still some work to do, but Weir's putting has been rock-solid all day and he bravely nails a six-footer to pick up another shot.
Weir acknowledges the crowd's cheers and strides off to the 16th with the look of a man who knows his time for Masters glory may have come.
Mattiace at hole 18
Mattiace drives right at the par-four final hole and his ball comes to rest on a bed of pine needles at the edge of some trees.
His line to the green is obscured and he is forced to chip out with a six iron sideways on to the fairway.
His third lands beyond the pin and ends up on the fringe of the green.
The American then nervously underhits his par putt and finds himself with a nasty six-footer for a bogey.
He sets his putt off left of the hole and it looks as if it might roll past, but at the last moment it edges right and topples in via the back of the cup.
Mattiace clenches his fist in relief but the damage is done - his dropped shot combined with Weir's birdie means there has been a two-shot swing and a play-off beckons.