American Kevin Kisner made a flying start as the third round of the 150th Open Championship got under way at St Andrews on Saturday.

Kisner, who made the halfway cut on the mark of level par, took advantage of glorious conditions for the early starters to birdie the first three holes and then pick up another shot on the fifth.

That took the 38-year-old to four under par and nine shots behind overnight leader Cameron Smith, whose halfway total of 131 had set a new record for an Open at St Andrews.

Smith enjoyed a two-shot lead over American Cameron Young, with Rory McIlroy and Viktor Hovland another stroke back, but the last group was not due out until 3.55pm.

“I think being off late again it’s obviously going to be a bit firmer, more like the first day I would say, so I would say it’s going to be pretty brutal out there,” Smith said after his stunning second round of 64.

“I think there’s going to be a few more gnarly pins, and I think being smart out there is definitely going to be the key to staying at the top of the leaderboard.

“I’ve always been a pretty good player in tough conditions. I think most Aussies are, for some reason.

“I think we’re all brought up to be smart golfers, hit away from the pin sometimes and that really serves us well, I think, in big tournaments and when the conditions get tough.”

McIlroy, who followed his opening 66 with a 68, will not change his strategy but is confident he can make inroads into the three-shot deficit as he seeks to win his first major since 2014.

“I know I’ve got the game. That’s all I need. I just need to go out and play my game and play my golf over the next two days and that’s all I can do,” he said.

“If Cam Smith goes out and shoots another two rounds like he did the first two days I’m going to have a really hard time to win the tournament. So I’ve just got to go out and do the best I can and worry about myself and hopefully that’s good enough.”