Swaraj's comment came in the backdrop of reports that she was not in the loop over government's decision to abruptly "curtail" Singh's tenure nearly seven months before it was to end.
"I told her that the Government wanted to appoint Dr Jaishankar as Foreign Secretary," Swaraj said in a tweet adding, "Then I spoke to Sujatha Singh personally."
Defending the government's decision to appoint Jaishankar in such a sudden manner, Swaraj said, "Since Dr Jaishankar was retiring on January 31st, we had to issue orders of his appointment before that date."
The 1977-batch IFS officer who had only two days to go for his retirement will have a two-year tenure as per the rules.
The sacking of Singh has come under criticism from Congress.