barmar, on 2019-September-10, 08:20, said:
If you look at the two big swings in our match, you will see that in each case my contracts were pretty good not even taking into account GIBs bad defense.
The first one was 4H on board 7. It is cold if the opps can't successfully attack diamonds as long as the spade honors are split. It is also cold if the diamonds are favorably located and the opps have not established their spade trick before it goes away on the diamonds. On the actual diamond lead with the diamond honors placed poorly for declarer, the contract is still cold if a long diamond trick can be established before the opps establish their spade trick. The last of these chances came through. So you can blame GIB if you want to, but it did find the killing opening lead - just not the killing defense after the opening lead.
The second swing (board 11) was 6S by me. The spade suit is Ax opposite KQT8x. The contract is cold if the spades come in (3-3 or 4-2 with a doubleton J) and has other chances. 6NT also makes when the spades run. According to Richard Pavlicek's hand analyzer, the chances of 3-3 spades or Jx in either hand is 51.68%. So 6NT is a small favorite. 6S is interesting, as 5-1 or 6-0 spades make the contract difficult to impossible. Still, I think it is better than 6NT. One of the opps will have Jxxx of spades 32.30% of the time. In those cases, it may be possible to get rid of both heart losers from dummy before the hand with Jxxx of spades ruffs in to cash the heart trick.
So the swings were not just bad defense by GIB.