Caitlyn Jenner Blasts Off 1st Golf Tourney as a Woman ... Crushes Drive!

Big day for Caitlyn Jenner ... she just teed off in her 1st golf tournament as a woman -- and SMASHED her first shot right down the fairway.

Jenner is participating in the ANA Inspiration Pro-Am in Rancho Mirage, CA -- playing in the same foursome as U.S. soccer legend, Abby Wambach.

For the record, Caitlyn's first swing looked GREAT -- confident, good follow through and powerful.

Abby looked okay ... but it's clear she's gonna have her work cut out for her if she wants to hang with CJ.

It's an 18 hole tournament ... so anything can happen. Stay tuned.