If a major Sunday at Oakmont is supposed to be tough, no one told Brooks Koepka.
The 26-year-old Tour winner is threatening to match or break Johnny Miller's record 63 in the 1973 U.S. Open at Oakmont.
After making bogey on two of his first three holes, Koepka went birdie, birdie, birdie, birdie, par, birdie, eagle, birdie over his next eight reach even par and pull to within seven shots of Shane Lowry's 54-hole lead.
The highlight of that run was his eagle on 10, where he holed out an iron from 108 yards.
Check out the video below, as well as his chip-in birdie on the next hole.