U.S. Open 2015 scores: Jason Day jumps into share of 54-hole lead despite battling vertigo

Jason Day could barely make it off the course under his own power on Friday. A bout of vertigo kicked in late in his round and forced him to drop to a knee multiple times and stagger his way in.

Despite the issues, Day was back out at Chambers Bay on Saturday and he turned in one heck of a round. He’s now at 4-under, tied with Jordan Spieth, Dustin Johnson and Branden Grace for the lead.

Day said he didn’t feel 100 percent at the start of the day and admitted to being “groggy” at times during the round. He didn’t take a knee or struggle like he did on Friday, but it was clear Day was far from feeling his best. His caddie said Day contemplated withdrawing three times during the back nine.

Chambers Bay is a hard enough course when you are 100 percent healthy, yet somehow Day managed to card a 2-under 68. The round was the second lowest of the day and arguably the most impressive considering the circumstances.

He was at his best coming down the back nine, carding five birdies on the back side to shoot a 31 coming in. His second nine could have been even better had he capitalized on driving the green at the 372-yard Par 4 16th. He had to settle for a par there, but quickly birdied his next two holes. He capped the impressive round with closing birdies at Nos. 17 and 18, thanks in part to sinking this long birdie put on the 17th.

Day will enter Sunday in the thick of contention as he makes another attempt to win the first major championship of his career. He will have to outlast an impressive group with Spieth, Johnson and Grace all looking capable of winning the tournament.

It was an up-and-down day for Johnson and Spieth. Spieth looked especially good early on, but tailed off during the middle of his round. He was able to regroup on the closing stretch, working his way into a tie for the lead with a birdie on No. 15. He nearly took the lead for himself coming down the stretch but just missed birdie tries at Nos. 16, 17 and 18.

Johnson struggled to pile up birdies without giving the shots right back. He frequently traded birdies for bogeys and recorded a costly double bogey on No. 13. While many players have struggled to make birdies, Johnson has tallied 15 in 54 holes. He appeared poised to take control of the tournament at a few different times, but each time it seems he runs into a stretch of trouble and falls back to the field.

Grace is the wild card of the co-leaders. He’s far from the household name Spieth, Johnson and Day are. While they are all ranked in the top 10 of the World Golf Rankings, Grace began the U.S. Open as the No. 40 player in the world. He’s been consistent throughout the week, hitting fairways and greens while putting slightly better than the field average.

With a four-way tie at the top, the stage is set for a tremendous final day at the U.S. Open. Here is a complete look at the leaderboard through 54 holes.