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 .