Opening Lead: ƄK
South won the ace and played another spade for West's queen as East discarded a heart. West continued with the ten and cleared the suit by playing a fourth round. With clubs breaking 3-2, declarer was assured of eight tricks, N-S +120.
South could have played a diamond at trick two to build a winner in that suit. East would score the king and would likely switch to a heart for the queen and ace. South would then have the option of driving out the king of hearts or the ace of diamonds for another eight tricks.
North wisely subsided when partner rebid 2NT since he held a bare bones minimum for the auction. Partner would have leaped to 3NT with game values.
A club contract yields nine tricks but North could not consider this action because a new suit would be forcing. South would then continue until game had been reached. In truth, he would advance to 3NT which has no chance unless West begins with an unlikely fourth best spade.
Fortunately, West did not receive an opportunity to rebid spades when opener rebid 2NT. A doubled one-trick set of a spade partscore would saddle West with a matchpoint zero.