Don't know if it qualifies as a greatest achievement, but I've had a game ending triple play. This was on a hit-and-run with Wagner catching a line drive and then throwing to 2nd and then 1st to double up the two runners.
Later this season we went on to win the World Series after rallying in the 9th inning in both game 4 and 5 of the NLDS when we were two and three outs respectively from elimination, the latter a three run comeback to tie and then win in the 10th.