Projected storms forced the R&A, the governing body of the British Open, to start a round from the first and 10th tees for the first time in tournament history. (Matthew Lewis/Getty Images)

For 142 British Opens, the R&A, which oversees the championship, had conducted golf in just one way: From the first tee through the 18th green. Though the two major pro tours, as well as the U.S. Open and PGA Championship, long ago gave way to the pressures of television and weather to get all competitors through in a reasonable amount of time, the R&A never wavered — until Saturday.

The third round of the British Open began at 9 a.m. Saturday at Royal Liverpool Golf Club from both the first and 10th tees, creating a wholly unfamiliar feel. The leaders went off from No. 1 at 11 a.m. — the same time Tiger Woods, at the rear, teed off from No. 10.

“Getting out a couple of hours in front of the leaders can often be an advantage if the wind was to get up,” Northern Irishman Graeme McDowell said.

That never happened. The reason for the move: projected thunderstorms through much of the middle of the day. But the worst kind of weather didn’t materialize. Play was conducted mostly in calm conditions, with occasional light rain. And the schedule completely shifted. When the final group of Rory McIlroy, Dustin Johnson and Francesco Molinari finished up, it was roughly 3:30 p.m., when the final twosome would normally be on its first few holes.

When McIlroy walked into the media tent following his round, however, the skies opened up.

“We didn’t move to a two-tee start lightly,” the R&A said in a statement. “The R&A much prefers a single-tee start and we’ll return to two balls all off the first tee [Sunday]. Given the weather forecast and the huge deluge around 20 minutes after play concluded we feel absolutely vindicated in making the decision we did.”

The lead group of McIlroy and Rickie Fowler is due to start the final round at 2:40 p.m. Sunday (9:40 a.m. Eastern time).

Woods falls way back

Woods would figure to be rusty given the fact that he arrived here with just two competitive rounds under his belt in the past four-plus months following back surgery. But after a miserable 73 in placid conditions — in which one double bogey and one triple bogey offset five birdies — he is at risk of posting his worst 72-hole finish at a major as a pro.

“I’ve just made too many mistakes,” said Woods, who sits at 3 over and is tied for 58th, 19 shots off McIlroy’s lead. “You can’t run up high scores like that and expect to contend, especially when the conditions are this benign. Most of the scores are 3 under or better. I certainly didn’t do that.”

This is Woods’s 65th major as a pro. He has missed the cut three times. When he has played the weekend, his worst finish is a tie for 40th at the 2012 Masters and the 2013 PGA Championship. His worst finish in a British Open in which he played four rounds is a tie for 28th in 2002.

Mickelson frustrated

Defending champion Phil Mickelson continues to say he is getting close, and his results continue to show otherwise. Mickelson has one top-10 finish worldwide this year (a tie for second in Abu Dhabi, though he has tied for 11th three times), and he played indifferently with a 71 on Saturday that left him 1 under for the tournament, tied for 34th.

“Oh my goodness,” Mickelson said. “I threw countless shots away — not shots, opportunities away all throughout the day. And it’s just frustrating. But I know that it’s not far off. But it’s got to click. It just hasn’t yet.” . . .

Annapolis’s Billy Hurley III made the cut in his first British Open but shot 76 on Saturday, including a triple-bogey 7 at the par-4 third, to sit 5 over. Hurley, who last month made the cut at the U.S. Open in his first major appearance, will join Charley Hoffman in the first pairing of the final round. . . .

Five-time British Open champion Tom Watson, 64, broke his own record to become the oldest competitor to make the cut, but he stumbled to a 75 on Saturday and is 5 over.