So many great games end up virtually forgotten just because they didn't have a decisive result. Here's a close call from the 1971 Fischer-Petrosian match, in which Fischer offers a speculative gambit in the Rubinstein French, Black defends well and turns the tables, ending up in a winning endgame, but in terrible time pressure. Trying to make neutral moves until adjournment, Petrosian overlooks a repetition (largely because it came about by a different move order on the final time), and the result is a draw, just barely.
It should be remembered again, that the 3-time repetition rule was not used in the Soviet Union, except in FIDE events, and as a result, Soviet players often forgot to apply it. For two other cases where Petrosian was bitten by this, check out Petrosian-Spassky, 1966, Game 12, and Castro-Petrosian, 1976. 1971