John Elway -- Dominates Fancy Golf Tourney ... Take THAT, Billy Bush!

John Elway still has it ... and he proved this past weekend by crushing his celebrity competition at a super fancy golf tourney event in Bel-Air ... TMZ Sports has learned.

Elway paired up with golfer J.J. Dudum for a special tournament at the Bel-Air Country Club last weekend ... where they faced off against other stars like Billy Bush, ex-NBC honcho Ben Silverman and fashion mogul Mossimo Giannulli.

Fun Fact -- Mossimo (the guy behind the Mossimo fashion line) is married to "Full House" star Lori Loughlin.

The good news for Elway ... he beat all of their brains out -- and people at the tourney tell us EVERYONE was impressed with the NFL legend's skills on the links.

At the end of the tourney, Elway and Dudum won the whole thing and #7 got himself another trophy for the case.