Mr Hashimoto, 42, had been the governor of the greater Osaka prefecture since 2008.
He recently resigned to run in the mayoral election.
He has proposed to reform Osaka’s administrative structure because he said the city hall and the prefectural office overlap in their functions.
“I hope civil servants at both institutions get the message from the voters this Sunday that they are not happy with your inefficiency,” said Mr Hashimoto at a news conference on Sunday.
The election generated a great deal of interest outside Osaka and the news conference was attended by at least 300 journalists.
Voter turnout in the mayoral election was also the highest in 40 years at 60.92%. For most of the last two decades, it had hovered below 40%.
Osaka’s economy lags behind the rest of Japan and needs any help that it can get.
The prefecture’s unemployment rate was the second highest in the country at 6.9% in 2010, and well above the national average of 5.1% according to the Statistics Bureau of the Ministry of Internal Affairs and Communications.
“At least one or two of our clients had been going bankrupt every month,” said Shigeyuki Suzuki, who sells photocopiers to Osaka construction companies.
“Some of Mr Hashimoto’s measures might be extreme, but without them, nothing will change.”
“We don’t expect things to change overnight, but we need someone like Mr Hashimoto to shake things up.”
His rival Kunio Hiramatsu was more conservative and was supported by all the major political parties including the Japanese Communist Party, which rarely backs the same candidate as the ruling Democratic Party of Japan and the main opposition Liberal Democratic Party.