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 predicted bookmakers would have offered odds of 4,000-1 on him being around for the weekend after a slow start to round two.

However, the 30-year-old 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.

“When you say only three people have shot 65 here and I shot 66 it sounds great, doesn’t it, but I was saying to everyone there was a score out there and I knew there was,” Enoch said.

“I was feeling so bad yesterday, though, I was just trying to tick each shot off at a time and get in the house. Once I started picking up shots round the turn I was back in it and the adrenaline gave me a lift.

“My caddie said it was the best round he had ever seen. It felt great to me but it didn’t feel like that. But I just shows what happens when you hit fairways.”

Enoch’s younger brother Ben was also a highly promising player, but was 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. “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 about 4:30am on Sunday I got slammed,” added Enoch, who secured his place at Pebble Beach via the 36-hole qualifier at Walton Heath.

“I had done too much in preparation. I got here Saturday and was a bit excited going round, then had a big gym session Saturday night. I didn’t practice on Tuesday and Wednesday so it was difficult. I’ve been playing well, though, so I’m just really glad I conjured some magic.”

“I’ve made the cut in my last two majors and that confirms what I’ve thought, that I am good enough if I can put it together.”

Enoch’s father Steve was a proud spectator at Pebble Beach and told Press Association Sport: “It’s a course that suits him, he’s very long. The par-five sixth he’s made eagle, birdie the last two days with a two-iron or three-iron approach up the hill.

“Thursday he was so poorly he did very well to break 80 to be honest. He struggled all the way through Monday, Tuesday, Wednesday and Thursday and then yesterday sort of started to get a bit better and back to himself and shot 66.

“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 eventually signed for a 73.

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.