Conor McGregor In Good Spirits For Birthday After UFC Injury, 'We'll Be Back!'

Conor McGregor didn't let his devastating UFC 329 injury ruin his birthday -- the MMA superstar spent it toasting with his wife and vowing (again) to return to the Octagon.

Notorious shared the video on Tuesday ... showing him testing out his Mac Energy product with Dee Devlin to commemorate his 38th trip around the sun.

It was a chill and calm affair -- no flashy gifts, antics, or yachts ... just soaking in the moment with his ride or die on a patio.

After the two raved about the flavor of their drinks ... McGregor flipped the camera and gave a thumbs up. As that happened, a crutch was briefly shown on the ground.

"We'll be back, we'll be back," McGregor said before going into prayer and kissing a rosary ring.

He then paused for a moment ... folding his hands and perhaps sending a private message to the Man Upstairs.

McGregor is relying heavily on faith after his loss to Max Holloway ... and previously spoke out about regaining a relationship with God after getting treatment in Mexico last year.

He also said before Saturday's loss, he fell into drinking while promoting his Proper No. 12 whiskey ... even though he hadn't been a fan of boozing too much prior. Opting for an energy drink could be a sign he's avoiding alcohol altogether these days ... especially since it's his birthday.

The post got some responses from big names ... like Jon Jones, who said, "This too shall pass, you can’t keep a good man down. Head high champ, happy birthday."

Longtime nemesis Jake Paul added ... "Happy birthday cutie pie 🤍 so proud of you."