"Doctors said the procedure was a success," Wendy tells TMZ Sports ... noting that she wants to thank everyone for their prayers and support during this difficult time.

As we previously reported, Flair was hospitalized on Thursday after suffering a medical emergency. He was supposed to undergo surgery on Friday, but doctors postponed the surgery due to "complications."

But clearly, they felt he was good to go on Monday -- because they operated as planned.

Unclear exactly what surgery was performed on Ric -- but we know he had been experiencing heart issues over the past few months and doctors felt his current situation was "very serious."

The 70-year-old wrestling legend has been in good spirits over the past few days and has been chatting with his famous friends on the phone, including Offset.

Flair had to pull out of a celebrity roast set for this upcoming Friday in Las Vegas -- but doctors are still optimistic he will make a full recovery.