This fascinating deal is from the Swiss Teams at Llangollen in early April.
After a quick auction West led the club ten. Declarer, Chris Pope from Merseyside won the ace, drew trumps in two rounds and exited with a club to East's queen. East played a third club, Chris trumped and ran trumps to reach the following end position.
On the last trump West discarded the club king, then ace and another diamond endplayed him to give declarer a spade trick. If West had discarded a small spade on the last heart declarer would just duck a spade and win the last two tricks. Nicely played by Chris, but East could have prevented the end position by returning a diamond when in with the club queen.
Could declarer have done better? Suppose he ducks the opening lead. Now if East returns a diamond at trick two South can just rise with the ace of diamonds, draw trumps and set up the diamonds with a club entry still in dummy, so East must return a club at trick two. Now declarer seemingly can reach the same end position as before. Not if the defence is really on the ball. West must unblock the high clubs and East must keep all his clubs. Now the end position is as below.
On the last heart West can discard a small spade and now exiting with a spade does not work as East can win two club tricks.