Last Summer the Belfast boxer became the first Northern Ireland boxer to win titles at two different weights when defeating Santa Cruz in New York.
Frampton had the first defeat of his professional career as he lost a majority points decision to Santa Cruz at the MGM Grand Garden arena in Las
Vegas.
Frampton gracefully said the "best man won".
"I want to apologise to the travelling support - the best man won on the night and I'm gutted."
Gary Lightbody, James Nesbitt and Michael O'Neill were ringside to support Frampton.