Hayden was told the news on Tiwi Island off the coast of Darwin when the chairman of the land council said: "Hey Matty, did you hear about the Irish fellah who broke your record overnight?"
O' Brien's century from 50 balls against England obliterated Hayden's previous best of 66 balls against South Africa in St Kitts during the 2007 World Cup, on what is the smallest playing arena in world cricket.
The Aussie legend said: "I couldn't believe it, it just didn't sink in that not only did he smash my record but he smashed the Poms as well -- something Australia found so hard to do in the Ashes.
"I was delighted and I'd like to pass on my heartiest congratulations to young Kevin for this amazing achievement, and trust that the remainder of the tournament goes well for you."
Hayden, who played 103 Test matches and 161 ODIs between 1993 and 2009, is founder of The Hayden Way, a company dedicated to helping the indigenous people and traditional landowners of Australia. But if the former opener still has any bats lying around, he might like to send them over to India for Niall O'Brien whose six Gray Nicholls were missing when he arrived in Chandigarh last night.