Brooks Koepka won his first major at the U.S. Open Sunday ... but it's his super hot model girlfriend who's the REAL winner.
Meet 28-year-old Jena Sims -- former Miss Georgia Teen USA -- who joined Koepka to receive his shiny Championship trophy after beating out stars like Rickie Fowler and Hideki Matsuyama.
She's also an aspiring model/actress who was in 'Sharknado' and an episode of "Entourage." And her social media photos are insane.
Here's hoping Koepka keeps winnin' majors ... 'cause we'd love to see some more of Sims.