Plymouth ensured their npower Football League status while denting play-off chasing Oxford's aspirations at with a 1-1 draw at Home Park.
Argyle made a dream start with left back Robbie Williams scoring from a 20-yard free kick in the second minute. Williams' curling left foot strike, following a foul on Luke Young, appeared to take a deflection as it breached the wall.
Young could have made it 2-0 seconds later but diving United keeper Wayne Brown did well to palm away the midfielder's first time half volley following a superb cross-field pass from Williams.
Oxford midfielder Asa Hall levelled with a sublime 35th minute right foot strike from 30 yards.
Fellow Us midfielder Adam Chapman came close to making it 2-1 in the 52nd minute when his free kick from the left flank came back off the far post.
It was the closest Oxford came to taking the lead during a nervy second half in which Plymouth boss Carl Fletcher introduced lively on-loan Burnley forward Alex MacDonald.