Jason Day’s caddie and longtime coach, Colin Swatton, believes his man had nothing left in the tank after giving it his all during the third day of the tournament when he played through the debilitating after-effects of a vertigo attack.

– Chambers Bay: Poulter and Horschel fume over US Open course
– US Open: Spieth keeps Grand Slam dreams alive with second major
– GALLERY: How Jordan Spieth won the 2015 US Open
– #360view: Critics were right about usuitable Chambers Bay

Swatton thought the Australian star had spent all his energy to get through Saturday’s third round, in which he bounced back in remarkable fashion and claimed a share of the lead with three birdies in his last four holes.

“He was totally exhausted. He was exhausted (on Saturday),” said Swatton. “I’m not sure how much of it took it out of him. I really don’t. It’s in the result. I don’t know what to say. I’m obviously disappointed.”

Day, who started the round tied for the lead at four-under par with the eventual champion Jordan Spieth, Dustin Johnson and Branden Grace, couldn’t get things going in the final round and closed with a four-over par 74 to finish at even-par for the tournament.

He made five bogeys and a double bogey, falling back into the pack with a rough three-hole stretch.

Day missed a 12-foot birdie putt at No11 and a six-footer at the 12th, then followed up with a double-bogey six at the uphill par-4 13th. A birdie at 16th was too little too late and Day said: “I had a lot of in-between clubs and started feeling a lot better after the 12th hole. That was a plus.

“I think I hit 13 greens and just didn’t capitalise at all on the stuff that I had. It’s unfortunate because I felt like I gave myself enough opportunities. Couple of putts, 11 and 12, go in and it’s a different story. If you don’t hole those, it doesn’t go your way.”

Day said he was going to take time off from the Tour and try and get to the bottom of the issue. Swatton said Day was struggling when he started the round.

“Early in the round he said he wasn’t feeling 100 percent and as the round went on, he sort of got into his groove a little bit,” Swatton said.

The tied ninth position was Day’s fourth top-10 finish in his fifth US Open start and the Australian expressed his thanks to the fans for their support.

“I was taken by the fact that so many people supported me. I really made a lot of Jason Day fans out there this week because I never gave up,” he added.