LeBron's Wife Hit Australian Fashion Show While Cavs Lost

LeBron James had a rough night ... but his wife was LIVING IT UP in Australia!!

Savannah James was spotted at Mercedes-Benz Fashion Week in Sydney, Australia on Wednesday ... rockin' some pretty cool lookin' sweatpants.

Of course, Sydney is 14 hours ahead of Boston -- where the Celtics beat the Cavs to go up 2-0 on Tuesday.

LeBron was laser-focused on Game 2 -- and showed up to the TD Garden hours before the game to shoot and prepare. Ultimately, it didn't help ... Cavs lost 107 to 94.

Meantime, there were a bunch of huge stars at MBFW ... including Shaun White, Joe Jonas and Elsa Pataky.