As simple as it was, the tactic from Chelsea to shoot all their penalties VDS' left hand side was very nearly perfect until Terry's slip and Anelka knowing VDS had clocked onto it.
I'm sure it's happened before, but don't recall a penalty shootout where one teams exclusively shoots to one side.
Real Madrid in 2016 final were similar and Oblak just kept diving the other way.
In 1995, the Basque economist Ignacio Palacios-Huerta, who was then a graduate student at the University of Chicago, began recording the way penalties were taken. His paper, “Professionals Play Minimax,” was published in 2003. One friend of Ignacio who knew about his research was a professor of economics and mathematics at an Israeli university.
It so happened that this man was also a friend of Avram Grant. When Grant’s Chelsea reached the final in Moscow in 2008, the professor realized that Ignacio’s research might help Grant. He put the two men in touch. Ignacio then sent Grant a report that made four points about Manchester United and penalties:
1. Van der Sar tended to dive to the kicker’s “natural side” more often than most keepers did. This meant that when facing a rightfooted kicker, Van der Sar would usually dive to his own right, and when facing a left-footed kicker, to his own left. So Chelsea rightfooted penalty takers would have a better chance if they shot to their “unnatural side,” Van der Sar’s left.
2. Huerta emphasized in his report that “the vast majority of the penalties that Van der Sar stops are those kicked to a mid-height (say, between 1 and 1.5 meters), and hence that penalties against him should be kicked just on the ground or high up.”
3. Cristiano Ronaldo was another special case. Ignacio wrote in the report: “Ronaldo often stops in the run-up to the ball. If he stops, he is likely (85%) to kick to the right hand side of the goalkeeper.” Ignacio added that Ronaldo seemed able to change his mind about where to put the ball at the very last instant. That meant it was crucial for the opposing keeper not to move early. When a keeper moved early, Ronaldo always scored.
4. The team that wins the toss before the shoot-out gets to choose whether to go first. But this is a no-brainer: it should always go first. Teams going first win 60 percent of the time, presumably because there is too much pressure on the team going second, which is always having to score to save the game.
From the book Soccernomics by Simon Kuper and Stefan Szymanski