21-year-old Onyenwerewas a star forward at UCLA -- and when the NY Liberty had the shot to take her with the 6th overall pick, they JUMPED!!
And, when Michaela's name was called, her grandmother -- decked out in an amazing festive outfit -- leaped out of her seat and yelled, "I'm grandma!"
The rest of the family smiled and clapped along -- it was awesome!
The other top moment from the WNBA Draft featured Tennessee star Rennia Davis.
ESPN had Davis lined up for a live interview after the Minnesota Lynx selected her with the 9th overall pick ... but Davis was so hyped watching her college highlight package, she forgot there was a camera on her!
Davis was literally shouting at the TV in her home while watching herself ball out -- pretty epic moment!!