Longest unbeaten run of games

Apparently this record belongs to USCF player Bill Martz who went 104 games without losing, but I have found this hard to verify.

Better documented is Mikhail Tal's run of 93 games. He lost to Petrosian in round 15 of the USSR ch. in Oct. 1973 and then went until Oct. 1974 without a loss. Kirov stopped his streak in the 4th round of Novi Sad.

Tal had a similar run a little more than a year before. He went unbeaten in 86 games from July 1972 when he lost to Uusi in the tenth round at Viljandi until he lost to Balashov on board 3 at the USSR Team ch. Moscow, round 2 in April 1973 +47=39

Kramnik 82 games from Jan. 12 1999 Euro club ch. Belgrade until he lost 4th round to Adams at Dortmund 2000

Tal 80 games 1980-1

Capablanca 63 games February 10, 1916 New York loss to Chajes to March 21, 1924 New York loss to Reti +40=23