Chile's Joaquin Niemann fired an eight-under par 63 in Sunday's final round to win LIV Golf Virginia in his final tuneup for next week's US Open at Oakmont.

The 26-year-old South American birdied four of the last five holes to finish on 15-under 198 after 54 holes at rainy par-71 Robert Trent Jones Golf Club in suburban Virginia.

"Being able to deliver today made me pretty proud," Niemann said.

Coming off his best major finish with a share of eighth in last month's PGA Championship, Niemann defeated India's Anirban Lahiri and Northern Ireland's Graeme McDowell by one stroke.

Niemann captured his record sixth career crown in the Saudi-backed series and took his fourth victory in eight events this season after wins at Adelaide, Singapore and Mexico City.

Niemann birdied four of the first eight holes to start his round then reeled off four birdies in a row starting at the par-five 14th to seize the lead.

"I felt like I was just behind all day," Niemann said.

"The only word I was telling myself from last night was just have faith."

He will test himself next week at Oakmont as he tries for his first major crown.

"I still feel like I'm pretty far away from winning one," he said. "I'm just happy to be playing at the US Open. It's going to be a great course, with pretty tough conditions. I'm looking forward to the challenge and to have a fun week."

Reigning US Open champion Bryson DeChambeau, in his final tuneup before defending at Oakmont, shared fourth on 200 with fellow Americans Phil Mickelson and Bubba Watson and Belgium 's Thomas Pieters.

Past US Open winners Jon Rahm of Spain and Martin Kaymer of Germany shared eighth on 203.

LIV's shotgun start was moved up to try and avoid bad weather but play was still interrupted twice.

Lahiri and McDowell shared the lead at 12-under when a 43-minute heavy rain delay struck.

Once play resumed, McDowell birdied 12 to seize the solo lead before a lightning delay struck and heavy rain began to flood greens.

Play resumed after 97 minutes and Watson grabbed a share of the lead with his third consecutive birdie, a tap-in at the par-five 14th.

Lahiri, Niemann, Pieters and DeChambeau birdied to make it six players tied for the lead before the Chilean pulled away.