Ludvig Aberg emphasised the importance of staying "disciplined and patient" after he took the sole lead of the US Open on Friday.

Aberg heads into the weekend with a one-shot advantage after carding a one-under 69, backing up an impressive 66 in his first round to leave him five under par at the top of the standings.

It leaves Aberg in a great position to become the second US Open debutant to win the tournament and the first since Francis Ouimet in 1913.

To achieve that, though, Aberg says he must remain calm, telling Sky Sports: "It's hard, but it's not supposed to be easy.

"It's what we expect coming into a US Open, even though it's my first one.

"I've had a lot of good discussions with my caddie Joe about course management and about trying to stay disciplined and patient.

"It's not easy, but I feel like we've done a great job of that so far."

Patrick Cantlay and Rory McIlroy held the joint lead heading into day two after both carding five-under 65s on Thursday.

However, McIlroy shot a disappointing 72 for his second round, while Cantlay's 71 leaves him as one of three players one shot behind Aberg, alongside Bryson DeChambeau and Thomas Detry.

The soaring temperatures have proved testing conditions for players and are expected to continue over the rest of the tournament.

Cantlay is predicting a difficult final two rounds, though he also said he was happy with the position he is in.

"I think this golf course is going to play very challenging over the weekend, especially with the forecast that we have," Cantlay told reporters.

"So I think being smart and being patient, it's inevitable there's going to be some mistakes made, but that's just part of playing a US Open."