South ruffed the club continuation, drew trump and claimed the slam, N-S +1430. North's reverse promised 17+ HCP with longer diamonds than hearts. South's spade rebid was forcing but did not necessarily promise a six-card suit. A 2NT rebid by South was available to show a poor hand. North raised spades since the doubleton king-queen constituted excellent support. South then launched into Blackwood to ask for controls with spades agreed. When the reply showed three controls, South continued with five hearts to inquire about the queen of spades. North's six diamond response promised the spade queen and the king of diamonds causing South to settle into the icy small slam. The minor suit slam also comes home with diamonds breaking normally but the major suit contract was superior and a higher scoring one which is always an important consideration at matchpoints.
Curiously, a seven club sacrifice would not yield a profit. There are six certain losers so that a doubled save would cost 1700 points! At favorable vulnerability, a save would be a profitable venture.