ST. ANDREWS, Scotland – Even by Open Championship standards, Thursday truly felt like the longest day in golf.

Pace of play slowed to a halt in the opening round at St. Andrews as threesomes, a 156-man field, drivable par 4s and reachable par 5s meant plenty of waiting and watching in the year’s final major.

“It’s quite stop-start, but I think St. Andrews is that way,” said Rory McIlroy, who shot 66 in a round that took 5 hours, 43 minutes to complete, even with a relatively early start time (9:58 a.m. local). “There’s a lot of crisscrossing and waiting on other greens and waiting on greens to clear because of the drivable par 4s.

“Especially the first two days, when it’s the full field, it’s to be expected,” McIlroy added.

McIlroy might have expected it, but his playing partners were caught by surprise at how much they stood around on a relatively calm day on the seaside links.

“I figured it would be slow, but I didn’t know it would be this slow,” Collin Morikawa said. “We were waiting on groups at tees, waiting on fairways. Xander [Schauffele] and I talked about it; we were watching more golf than we ever have. You stand in the fairway, and you’re watching two other groups play golf. That’s part of it this week, just staying patient and making sure you’re not rushing your shots.”

There are a couple of unique issues at play, from the Old Course’s seven double greens to some of the fastest conditions The Open has had in recent memory, which creates longer waits on the tee as the group waits for the fairways to clear. The course measured just 7,244 yards in Round 1 but played drastically shorter because of the rolling, running fairways.

“I guess when it’s firm and the ball is rolling out to 400 yards,” Schauffele said, “everyone is going to wait.”

Somehow, the pace slowed even more by the afternoon wave.

The featured group of Tiger Woods, Matt Fitzpatrick and Max Homa, starting at 2:59 p.m. local, needed five hours just to get through 14 holes. In the end, they finished in about 6 hours, 10 minutes.

“I felt like I needed to call my [physical therapist] and get him to stretch me back out,” Homa said. “It was just an insane amount of waiting.”

The first two rounds of The Open are always among the longest in golf, with a one-tee start that begins at 6:35 a.m. local and wraps up with the last three-ball at 4:16 p.m.

Sunset at St. Andrews on Thursday was at 9:51 p.m., though the final groups played well into the 10 p.m. hour. First-round play was ultimately completed at about 10:30 p.m.