PARIS — You might think that playing 38 tennis matches against someone would mean there is very little left to learn before the 39th.

But that is not the way Rafael Nadal, Roger Federer and their teams have approached their French Open semifinal on Friday.

Both men and their coaches have been scrutinizing data and examining video clips in an attempt to find an edge, looking for a new pattern, a new weakness, a new reason to believe.

“I like to analyze,” Carlos Moyá, Nadal’s coach, said on Wednesday. “I like to try to find a crack in the opponent’s game and to try to see what I would do if I were the opponent’s coach to try to hurt Rafa and then try to find solutions to that. So it’s like chess.”