To become a world champion one has to play well, of course, but some luck is needed as well. Observe what happened in the Round Robin of the 1993 World Championship teams (contesting the Bermuda Bowl). Netherlands played the ever tough Indonesian team and was presented with 12 easy IMPs in the following way.

N/All		♠	9 7
		♥	Q 9 3
		♦	8 4
		♣	A Q 7 6 3 2
♠	A J 10 4 2			♠	K 5 3
♥	K J 10			♥	8 7 6 2
♦	J 5 3			♦	K 7 6
♣	J 8			♣	10 5 4
		♠	Q 8 6
		♥	A 5 4
		♦	A Q 10 9 2
		♣	K 9

At both tables South became declarer in 3NT, after identical auctions.
In the open room Dutch EW-players Jansen-Westerhof effortlessly collected the first five spade tricks: down one.

In the closed room West (Munawar) leads a spade as well, the ♠10 to be exact. East wins with the ♠K (South the ♠6) and returns 'a' (!) small spade. South, Westra, unhesitatingly produces the ♠Q.
West wins with the ♠A. However, for a few seconds he has lost his concentration: he failed to register which small spade his partner played back. It was not the ♠8, that much he knows. But whether it was the ♠5 or the ♠3, he hasn't noticed.
If East's card was the ♠5, the spade suit must have been distributed as in diagram 1 (red cards have been played):

diagram 1		♠	9 7
♠	A J 10 4 2			♠	K 5 3
		♠	Q 8 6

Like all good pairs EW return the higher of two remaining cards in a suit. So by playing the ♠5 back (from ♠53), East has shown that – at the moment of playing (!) – he had an even number of spades left. He must have started with ♠K53 then* (after all, from ♠K85 he would have returned the ♠8).
If so, West must now play the ♠J and then cash two more spades: down one.

But if East has returned the ♠3, this* must have been the layout in spades:

diagram 2		♠	9 7
♠	A J 10 4 2			♠	K 8 5 3
		♠	Q 6

By playing back his lowest spade (the ♠3 from ♠853), East has indicated he had an odd number of spades – at the moment of playing.
If so, he now has ♠85 left and the spade suit will be blocked if West plays back the ♠J in trick three. West must play back the ♠2 or ♠4 therefore: his partner wins with the ♠8 and returns the ♠5, after which West makes the ♠J and cashes his fifth spade: down one.

West ponders for a long time and finally decides to play Westra for the original holding of ♠Q6, since the Dutchman played the ♠Q unhesitatingly in trick two. So West assumes the layout to be that of diagram 2 and plays the ♠2 in order not to block the suit!
Westra gratefully wins with the ♠8 (since diagram 1 shows the actual layout) and cashes eight more tricks, to score +600 and a 12 IMP profit.

* Couldn't East have started with ♠K5 or ♠K3 respectively? True, but then South, having ♠Q863 or ♠Q865 respectively, had a spade guard all along. By the way, he probably wouldn't have played the ♠Q then, but a small one (although playing the ♠Q doesn't even cost after this lead).

An unexpected 'beginners' mistake' by West therefore (but keep in mind that participants in international championships play many deals every day, during many days; top players are only human and due to fatigue even they sometimes fail to register a spot card).
Still: hadn't Westra played that ♠Q so quickly and attentively, West couldn't have gone wrong. That is the hallmark of real top players: they create opportunities for opponents to go wrong.