Shaquille O'Neal wasn't a sore loser after his alma mater LSU shockingly fell to Colorado on Monday ... 'cause the Big Fella made an awesome gesture by congratulating the Buffaloes in the locker room!!
The No. 20 CU women's hoops team pulled off the major upset over Angel Reese, Hailey Van Lith and the No. 1-ranked Tigers in a 92-78 victory in Las Vegas ... stunning the defending champions in the season opener.
But Shaq -- who dominated in Baton Rouge from 1989-1992 -- wasn't too bummed to be a good sport for the big winners of the night ... sharing a postgame moment with head coach J.R. Payne and the athletes.
"Good game girls," Shaq said as he also shook hands with Payne.
O'Neal wasn't the only big name to show love for the Buffs -- three-time WNBA champ Candace Parker also gave the squad some motivation for the season.
"Hope to see you in the Final Four," she said.
Of course, the LSU women's team skyrocketed in popularity en route to winning it all earlier this year ... with Reese and Flau'jae Johnson becoming big names in the sport.
But CU clearly didn't seem fazed by the Tigers' star power -- putting on a shooting clinic to get the dub.