"I welcome [Bernero] to the race, I'm looking forward to the campaign," Mayor Benavides said Friday.
But he described his opponent's decision to run as "a waste of money."
Benavides defeated Virg Bernero by only 258 votes in 2003. The mayor said he isn't expecting a close race this year.
"This time it should be totally different, this time there should be a large percentage in my favor," Benavides said.
Like Sen Bernero, the mayor said he expects jobs and the economy to be key issues in their debates.
"My two years experience as mayor and my many years in the city council show that I'm still the man for the job," he said.
Bernero officially entered the race Thursday. The election is in November.