The U.S. Open at Congressional Country Club was, in fact, a year ago. By now, it should be cleansed from day-to-day discussion, a nice memory of a worthy champion setting record upon record in Bethesda. PGA Tour golf has returned, and that should mean nice, leisurely rounds, birdies aplenty — essentially, what accidentally happened in 2011 at a major championship that so many considered a minor disappointment.

But between the rivers of sweat and the drained water bottles Thursday at Congressional, the AT&T National turned into a pretty decent Open impersonation. No one went crazy low; indeed Bo Van Pelt’s first-round lead of 4-under-par 67 was two shots higher than Rory McIlroy’s opening 65 a year ago. It all led Tiger Woods, the man who brought the AT&T National here but missed last year’s Open with injuries, to say an Open “broke out” on Thursday, albeit a year off schedule.

“It’s certainly, I think, a little retribution for what happened last year,” said Woods, who opened with 72. “Don’t be mad at me. I didn’t play.”

So here comes Congressional, ready to fight back. The field of 120 will be left Friday to fight temperatures that could approach triple digits, a golf course that is firm and fast, and their own ideas of what a PGA Tour event should feel like. Have the tour pros faced a course this difficult this year?

“Probably not,” Van Pelt said.

“I can’t think of one that was harder,” said Billy Hurley III, the Leesburg native and Annapolis resident who opened with 69.

The candidates would include Torrey Pines, which has also hosted an Open. Woods threw in Bay Hill, the Orlando course on which he won in March, because its Sunday set-up was so difficult. But 4 under has led after one round at just four of 28 PGA Tour events this year — the RBC Heritage in Hilton Head Island, S.C., the St. Jude Classic in Memphis, the U.S. Open and here. Every other tournament has produced a first-round leader more shots under par.

All this makes sense to Woods. He made his first bogey after a wayward drive at 4, got it back with a birdie at 9, but then came to a hole that has long troubled him, the 489-yard par-4 11th. He pushed his tee shot right, on the opposite side of a creek that runs alongside the fairway.

“I was angry at myself,” he said, and when he chipped out short of the green, he found a divot. Another bogey resulted, and a difficult day — one that fit right in with those of so many others — was under way.

“A couple of shots today,” Woods said, “the ball was bouncing as high as it flies.”

So after one day, McIlroy’s 16-under total of 268 — both Open records — seem unlikely to be matched. There are, though, those here who can draw from that week. Van Pelt, for instance, was one bad day away from truly contending last year at Congressional. He shot 76 in the first round, and figured to have to scratch and claw his way to the weekend. He responded with rounds of 67 and 68, and he ended up tied for 14th, his best finish in any U.S. Open.

But even as he shot those scores, he was left well behind McIlroy’s wake. And he had one thought back then: 2011 should have been 2012.

“I said it last year,” Van Pelt said Thursday. “They needed one more year. And basically, you could have a U.S. Open here this week if you wanted it.”

The reasons an extra year was needed had most to do with the greens, which were completely dug up and rebuilt in the summer of 2009. The thinking: Another year would have given the roots more time to take hold, and they could have better endured extreme heat that preceded last year’s open. They would have been firmer, slicker.

But the situation the players face this year is, too, tough for other reasons. The rough may not be as high a year ago, at least well off the fairway, but it is dense. A year ago, hit a stray tee shot, and there was a chance a player could catch a break in an area of thin rough. This year?

“The rough is very uniform,” Van Pelt said. “It’s very thick.”

In 2011, after one round, McIlroy’s closest pursuers, Y.E. Yang and Charl Schwartzel, each shot 3-under 68. Thursday, Van Pelt’s closest pursuers — Vijay Singh, Brendon de Jonge and Jimmy Walker — also shot 68. Thirty-three of 156 players shot par or better in the first round of the Open; 22 of 120 did so Thursday on a set-up that’s supposed to be easier.

Then, too, there is the heat. By Friday afternoon, the temperature is predicted to be over 100, with a heat index that could make it more uncomfortable — or even dangerous.

“Once it becomes physical, it becomes psychological and mental,” said Hunter Mahan, one in a group who shot 70. “You can make mental mistakes if you’re tired. . . . If you’re tired and you’re not hydrated, it’s going to be tough.”

It already is tough. At quarter to 6 Thursday evening, Woods stood at the back edge of the 18th green and looked across the pond at a leader board. He stood five back. But with 54 draining holes to go — holes that might be played under conditions seen only occasionally on the PGA Tour — plenty of those ahead of him could wilt.

“It’s survival,” Woods said. It is a phrase usually reserved for a U.S. Open.