Cambridge recorded their first Varsity Match success since 1998 after centre Simon Frost stunned favourites Oxford with two early tries in a 15-13 win at a freezing Twickenham.
Dark Blues fly-half Matt Honeyben had a golden chance to tie the game late on, yet his conversion attempt of Canadian international prop Kevin Tkachuk's 72nd-minute try drifted wide.
Frost, a 24-year-old with appearances for Swansea and London Welsh under his belt, was the Cambridge hero.
He exposed Oxford's defensive deficiencies by touching down after nine and 16 minutes, and although the Dark Blues replied through wing Will Rubie's well-worked score, Cambridge never looked like relinquishing a 12-5 interval advantage.
Fly-half Owen Edwards' second-half penalty ensured that they lifted the MMC Trophy, denying Oxford's American lock Adam Russell an unprecedented fourth individual Varsity win in the process.