Savannah Guthrie is re-entering the celebrity social scene ... making her first red carpet appearance since her mom, Nancy, went missing.

The "Today" host posed before the US Open Exhibition Match event in New York City Tuesday evening ... wearing a stunning black floral dress.

She accessorized with some exquisite jewelry and flashed a close-lipped smile for the camera as she stopped for a few quick pics.

Savannah watched the tennis action with her husband, Mike Feldman.

Roger Federer and Andy Roddick played in a singles match at the event ... then Federer and John McEnroe played Roddick and Andre Agassi in a doubles exhibition.

Savannah is a longtime tennis fan ... and for the last three year's she's attended the US Open.

The NBC anchor has been slowly getting back to some semblance of normal since Nancy went missing from her Tucson, Arizona, home in February.

It's been almost 7 months ... and the search continues.

As we reported ... a never-before-seen note revealed Nancy may have died just days after she was initially kidnapped from her home.

Savannah has already returned to "Today" ... but this public appearance marks another huge step forward for the TV personality.