Thomas' record yet to sink in as he eyes first major title

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Justin Thomas had yet to realise the significance of his record-breaking U.S. Open round on Saturday as he focused on contending for a first major title.

The American lit up Erin Hills in round three, firing a nine-under 63 to post the lowest score to par in the tournament's history.

Thomas, 24, charged into first place with the aid of nine birdies and a wonderful eagle at the 18th, but will begin Sunday a shot behind Brian Harman, who subsequently took over at the top of the leaderboard.

A four-time winner on the PGA Tour, Thomas was simply pleased to be in contention after his tremendous round.

"I'm not sure when it's going to sink in or when I'm going to realise what I did," he told a news conference.

"I know one thing, if it happened tomorrow [Sunday] and the result is what I want it to be, then I'd probably have a little different feeling. But I'm just so excited to give myself a great chance to win this golf tournament.

"I felt like my game has been good enough to compete in the majors this year. So to be able to do so and have a chance tomorrow is just going to be great."

With his 63, Thomas was just the latest player to make the most of unusually good scoring conditions at a U.S. Open site.

Patrick Reed carded a 65 on Saturday and Rickie Fowler, Hideki Matsuyama and Chez Reavie all managed the same number in the opening two rounds.

While stronger winds are expected on Sunday, Thomas - yet to finish in the top 10 of a major - said the soft greens during the third round helped.

"Being this soft, birdies are going to happen. You never know how the USGA is going to set it up tomorrow," he said.

"It was definitely conducive for good scores today. You could get after it a little bit. It doesn't matter how long, how whatever the course is. When you give us soft greens, good greens and not much wind, you know there are going to be some good scores. I was just happy that I was the one that was able to take advantage of it today.

"But it's going to be weird. I don't know what I'm going to feel tonight, if I'm going to sleep well. I'm sure I won't sleep in. I usually don't. So I'm pretty much docking that for tomorrow, and figure I have no chance to sleep in.

"I know I'm going to be nervous, but it's a good nervous, that's why I play to get myself in this position. And I'm excited for the opportunity to see what happens."