"I thought Elizabeth Warren wasn't running for president," Christie said in an exclusive interview on ABC's "This Week." "Mrs. Clinton doesn't hear from anybody, she doesn't talk to anybody, she doesn't take questions from anybody. How would she know what real Americans are concerned about?"
"I know how to fight when I need to," Christie said.
The governor added that Donald Trump should be considered a viable candidate.
"Donald has been able to sell almost anything over the course of time and the fact is you have to take him seriously if he decides to run," he said.
Christie also spoke about debt-free college tuition, which he discussed earlier this week in Iowa, saying costs needed to be contained but added "there is nothing free in this world. We need to earn what we get."
In recent weeks, Christie has called for Congress to expand its student aid programs, including the Federal Pell Grant Program.
Christie is expected to decide whether he will run for president by the end of this month.
"If I decide to get into the race, I'll take anybody on," he said. "I have a day job."