Alcohol Free finished strongly to overcame favourite Poetic Flare and win the Sussex Stakes at Goodwood.
The 7-2 winner, trained by Andrew Balding, swooped on the outside to beat 11-8 shot Poetic Flare by one-and-three-quarter lengths.
For owner Jeff Smith, seeing Oisin Murphy ride the three-year-old filly to victory ended a 37-year wait between Sussex Stakes wins.
"This filly is something else," Smith said.
"The way she has won that, it's simply incredible. I'm thrilled to pieces, and what a wonderful job Andrew and the whole team have done."
Smith last won the race in 1984 as owner of Chief Singer, while he has also celebrated Goodwood success with Lochsong and Persian Punch.
After a slow early pace in the Group One mile race, Century Dream upped the tempo a long way out, with Poetic Flare taking the lead as they entered the final furlong.
Murphy delayed his challenge on Alcohol Free and quickened impressively to triumph, with Poetic Flare second in front of third-placed Snow Lantern (6-1), who made up late ground but failed to trouble the two frontrunners seriously.