Wladimir Klitschko chases the 17th defence of his world heavyweight crowns against unbeaten Kubrat Pulev on Saturday with the legendary Joe Louis' record of 25 defences in the division getting closer.
The 38-year-old Klitschko has held at least the IBF and IBO heavyweight titles since 2006, adding the WBO title in 2008 by beating Sultan Ibragimov, before a unanimous decision against Britain's David Haye in 2011 gave him the WBA crown.
It says as much for Klitschko's longevity as the lack of genuine contenders that the giant Ukrainian has had few peers in the division.
Klitschko takes on Pulev in his home town Hamburg's O2 World, near the Imtech Arena where he beat Haye more than three years ago.
The Bulgarian has earned his first world title fight by becoming the IBF's mandatory challenger.
The 33-year-old has 11 knock-outs in 20 victories on his unblemished record, but sparked animosity when he boycotted Monday's pre-fight press conference having been left fuming after members of his promotional team were denied access.
"Because Klitschko is not behaving correctly, he doesn't get my respect," said Pulev. "He isn't afraid and he will be tested (during the bout)."
The Ukrainian champion pulled out of the original fight in September due to a bicep injury and was unimpressed by the challenger's pre-fight behaviour.