Petrosianic: Unfortunately, this is one of the few games that's totally unannotated in the tournament book.
There are several interesting Petrosian games from this tournament, such as
Petrosian vs Saidy, 1972
Where Petrosian puts him to sleep with quiet play and traps Saidy's queen in the middle of the board in a position where it looks like nothing is happening.
Petrosian vs Larsen, 1972
Great slugfest with errors on both sides.
Mecking vs Petrosian, 1972
Interesting ending, and a good Black win with the Burn French.
Portisch vs Petrosian, 1972
Tough game from the days when Portisch seemed to have his number, but he manages to hold the day with one of his patented exchange sacs.
Though when I think of San Antonio 1972, this is the first game that comes to mind:
Larsen vs Keres, 1972
Typical of the frustrating games that drive Larsen fans crazy. While leading the tournament, he pushes much too hard to win a drawn game, commits a gross blunder, loses, and slides back into the pack. Shades of Larsen-Fischer, Game 2.