Infield Fly?

[Mark Dexter]

Okay - so I thought I was finally starting to understand the IFF rule, but I was confused by a situation in today's Mets-Tigers game.

1 out, runner on 1st, when the batter hits a pop fly to fair territory right in the vicinity of 1st base. F4 comes over to field the ball, but he doesn't make the catch. F4 throws to F3 (who's on the bag), but the throw is late and the BR reaches first safely. F3 then throws to F6 (who's covering second) and forces out a very confused R1.

I thought that the BR would be out on an infield fly, and R1 would have to be tagged to be put out. Did anyone see the play? Alternatively, can anyone correct my misunderstanding of the rules?