At the Continental Tour Gold level event in Chorzow, 27-year-old Vetter, who won gold at the 2017 worlds in London, came to less than a metre of three-time Olympic champion Jan Zelezny's 1996 world record of 98.48m.
"I don't really know what to say, in javelin there are little details that make it possible to make very good throws, when everything fits perfectly," said Vetter.
"With a headwind I could have gone much further, maybe close to 100m, but I think I showed that you can also throw very far in a closed stadium like this."
“I can’t remember the throw – I can just remember that I was crying … It’s not usual that you throw that far.”@jojo_javelin threatens javelin world record with 97.76m throw at @MemorialKamili. : https://t.co/asYqQJw87g#ContinentalTourGold pic.twitter.com/h9QanzD0XC — Continental Tour Gold (@ContiTourGold) September 6, 2020
German Vetter's throw was also more than three metres further than his previous personal best, and moves him nearly four metres ahead of the next best throw, compatriot Thomas Rohler's effort of 93.90m in 2017.
Vetter was fourth at the Rio Olympics in 2016 and third at the worlds in Doha in 2019.
He has been in impressive form this season with a throw of 91.49m on August 11 in Turku, Finland.
Even after his victorious throw on Sunday, he even allowed himself to throw 94.84m on his fourth attempt, the sixth best performance in history.
Speechless! 97,76m - New National Record, Meeting Record - World Lead - 72cm close to the World Record! Dziękuję @memorial_kamili_skolimowskiej @contitourgold #VetterWurf Paweł Skraba https://t.co/cc4kB45tsa pic.twitter.com/qnyVuqmOZm — Johannes Vetter (@jojo_javelin) September 6, 2020
After his 2017 world title, Vetter's progress slowed over the last two years due to a persistent left ankle injury where a piece of bone moved freely.
That required injections before each competition.
Operated four days after the worlds in Doha last October, he resumed training at the end of November.
His next event will be on Tuesday in Dessau, Germany, followed by Berlin on September 13.