Six-time runner-up Phil Mickelson will not be the only player celebrating their birthday in Sunday's final round of the US Open after Welshman Rhys Enoch defied illness and his lowly world ranking to shine at Pebble Beach.

Laid low by a chest infection at the start of the week, Enoch struggled to an opening round of 78 on Thursday and admitted he was thinking "get me out of here" after a slow start to round two.

However, the 30-year-old from Truro rallied to post a brilliant 66 – only Tiger Woods, Justin Rose and halfway leader Gary Woodland have ever shot lower in a US Open at Pebble Beach – to make the cut on the mark of two over par.

That meant a third round alongside former Masters champion Patrick Reed on Saturday and although Enoch could not maintain his momentum after two early birdies, a level-par 71 meant he outscored Reed by a shot.

Enoch's younger brother Ben was also a promising player but was tragically killed in a car accident 10 years ago last month on his way to compete in the Lytham Trophy.

"I had a little think about Ben afterwards," Enoch said following his second round. "It is 10 years since he died, but he is always with me. He would have loved this."

Rhys was in college in the United States at the time of his brother's death and after graduating from East Tennessee State in 2012, his professional career got off to a nightmare start after he contracted glandular fever.

"I still get flare-ups now and I was in bad shape from Sunday," added Enoch, who secured his place at Pebble Beach via the 36-hole qualifier at Walton Heath.

"Apparently there's not been many scores better than that in a US Open at Pebble Beach, which is good, and he's playing well."

England's Tommy Fleetwood was also among the early starters after holing from 14 feet for a bogey on the 18th on Friday evening to make the cut on the mark.

Fleetwood, who was fourth to Brooks Koepka in the 2017 US Open and second to the same player last year, made the ideal start with a birdie on the first but ran up a double bogey on the third and dropped another shot on the eighth before carding a second birdie of the day on 16.

Woodland's record-equalling 65 on Friday gave him a halfway total of nine under par and a two-shot lead over 2013 winner Justin Rose, with former Open champion Louis Oosthuizen a shot further back and Rory McIlroy alongside American Aaron Wise on five under.

Defending champion Koepka, who is seeking a hat-trick of US Open titles and a fifth major victory in his last nine starts, was ominously placed on four under in a group which also contained England's Matt Wallace, who was third in the US PGA Championship behind Koepka last month.

Graeme McDowell, who lifted the trophy at Pebble Beach in 2010, was three under par after a round of 70, with Masters champion Tiger Woods nine strokes off the pace following a disappointing 72.