No round of professional golf can be played on the Blue Course at Congressional Country Club without, it seems, comparing it to the events of two years ago, the 111th U.S. Open in which Rory McIlroy appeared to make a mockery of the place.

“It played just like it,” Lucas Glover said early Thursday afternoon, after his first round in the AT&T National. “Actually played harder.”

That may not play out over the rest of the tournament, but on a cloudy, comfortable Thursday morning, it could hold up. With the morning wave of players completing their rounds, Billy Horschel, a 26-year-old Florida grad who two weeks ago shared the lead of the U.S. Open through two rounds, managed the best round thus far, a 3-under-par 68 that provided a one-shot lead over former Open champ Jim Furyk, Belgium’s Nicolas Colsaerts and Ben Kohles, a 2012 University of Virginia grad who’s a PGA Tour rookie.

“If you get to 1 under or 2 under, you’re not thinking, ‘Oh, I can get to 66,’” said Nick Watney, who joined a large group at 1-under 70.

If there’s a 66 — which would be one shot higher than the round McIlroy opened with in 2011 — it will have to come in the afternoon, when Masters champion Adam Scott and fellow Australian Jason Day are among the top draws. The morning wave found a long, difficult golf course on which the thick rough offset soft, receptive greens.

“I was surprised when I got to the seventh tee, and I looked out and saw that I was tied for fourth or fifth,” Furyk said, “and was kind of scratching my head going, ‘Wow, scores are pretty tough today.’”

Thus begins the debate — again — about whether a PGA Tour event should be held on a setup that resembles the U.S. Open, which annually bills itself as the toughest test in golf. At 7,569 yards, Congressional is playing just five yards shorter than the U.S. Golf Association’s setup in 2011, and the fairways are just as narrow. That year, the course was victimized by extreme heat in the weeks leading up to the Open, and the roots of some of the rough died, thinning it out. Now, that’s not the case.

“The tougher the golf course, the better I like it,” Horschel said. “I don’t like easy ones. I think you should be penalized if you hit a bad shot.”

The flip side of that: Glover said he heard two cheers all morning from galleries that were already thin because Tiger Woods, the event’s host, is sitting out because of an elbow injury.

“I’m fine with hard golf courses,” Glover said. “But make it fun. Make it fun for us, make it fun for the fans. That’s what we’re here for. We’re here to entertain these people that pay a lot of money to come watch us play golf. Not try to make par. . . . We’re supposed to show these people how good we are, not how we can chip out of the rough.”

McIlroy famously took advantage of the conditions at Congressional to set Open records for scoring, a four-round total of 16-under 268. Last year, Woods won at 8-under 276.

“It’s like another U.S. Open,” Horschel said.

One person who can’t compare: Kohles, who had never played Congressional before this week. But that pretty well describes his year. Last season, when he barely failed to qualify for the U.S. Amateur, he wrote a letter to the tournament director of the Tour event in Columbus, Ohio, and received a sponsor’s exemption based on the fact he was a three-time All-American for the Cavaliers. He won the event, then won the next week, and suddenly had a job.

“I was probably going to play on the mini-tours and try to go through Q-school,” Kohles said. “To kind of get that in the first week right out of the gate, and I had a spot to play the next two years, definitely took a lot of pressure off.”

That performance got him a spot on the big tour this year, and his best finish was a tie for seventh in Tampa. But he came to Congressional having missed six cuts in his last eight events.

“It’s been pretty tough, and it gets a little frustrating,” Kohles said. “But you just kind of keep your head down and say to yourself, “Every week is a new week and you’re playing for a million dollars.’”

Storms could interrupt play this afternoon, and that could push the second round into Friday morning. But the tone at the AT&T National has already been set.

“It’s a long, hard golf course,” Furyk said.