Tiger Woods made bogeys on his final two holes Friday to finish at even par through two rounds of the U.S. Open. (Marcio Jose Sanchez)

In what seems like a blink, two golfers have become the central focus of their sport. Brooks Koepka arrived. And Tiger Woods returned. In a game full of superior players and fine story lines, they stand apart.

Just 24 months ago, Koepka, who had only one PGA Tour win at the time, won the 2017 U.S. Open. Since then, he has arrived full-blown — a four-time major champion at 29.

Just one year ago, when he missed the cut at the U.S. Open, Woods was a shadow man from the game’s past. Since then, he has repeatedly contended in majors, won the Tour Championship, won the Masters in April and is back ranked No. 5 in the world.

Now, Tiger talks about his future — perhaps 10 years of it, if all his hopes fall in place. But he suddenly discovers an extra obstacle in his quest to pass Jack Nicklaus’s record of 18 major championship wins.

His new problem: Koepka.

Brooks Koepka made a late rally to get to 4 under par after two rounds at the U.S. Open at Pebble Beach. (Etienne Laurent/EPA-EFE/REX/Shutterstock)

On Friday at the U.S. Open at Pebble Beach Golf Links, Koepka and Woods faced an identical challenge. Both were playing well enough, at 2 under par, but both were also watching the leader at the time, Justin Rose, move away from them at 7 under.

With nine holes left in their second rounds of this Open, who could hit the gas and close the gap? And who might blink and fall behind?

The contrast between age and youth, between an all-time great in his 40s and the hot champion of the present in his prime, is always cruel in sports. On a golf course, where each player stands alone with his excellence on display or his errors exposed, the gap is especially stark and undeniable. It’s one reason we are moved so deeply when the old player prevails, as Tiger Woods did in April at the Masters, and celebrates his win with tears of joy and near disbelief.

But usually it doesn’t work that way. Usually age just looks tired while youth relentlessly shows its teeth. Usually Koepka, who has won two PGA Championships and two U.S. Opens in the past two years, surges into contention with a pair of late birdies at exactly the moment when he needs to produce his best.

And the 43-year-old, like Woods here Friday, finishes his day bogey-bogey to slit the throat of his main chance and come off the course boiling after 36 holes.

“Tiger, are you steaming?” was the first question Woods received.

“Yeah, I am. Not a very good finish,” said Woods, who now responds with honesty to the same questions he might once have greeted with haughty disdain. “I’m a little hot right now. I just signed my card about a minute ago. So, need a little time to cool down a little bit.”

Just minutes earlier, Koepka was asked about his day. “Fun . . . big confidence boost,” he said. “I was hitting good putts. My ball-striking was tremendously better [than Thursday]. Never felt like I had to work hard. . . . I’m good at this patient game. You just need to hang around on the weekend. I’d like to be leading, but you never know when [putts] might all go in.”

By the end of the second rounds, Koepka (69-69) had battled his way to 4 under, just five shots off the lead and in a tie for sixth place — a serviceable spot to start the weekend. But Woods (70-72) had dropped to even par, tied for 32nd, thick in the middle of the struggling pack.

That’s when we realize that, no matter how amazing it is to see Woods as a top contender once more — and he was the third choice in betting for this Open — his chase of Nicklaus is going to require years of health, hard slogging, clutch play at key spots and good breaks, too. Tiger doesn’t just need to win four more majors to pass Jack. He has to do it right in the teeth of what may be the era of Koepka.

So, days such as this have an especially sharp sting.

As Koepka and Woods made the turn, separated by only one group, which man was going to join the chase and get close enough that Rose would see him in the rearview mirror? Who would be in position to play for an Open trophy Sunday evening when Rose, who has won one major championship in 21 sublime seasons on the golf scene, would probably turn back into himself and play pretty well, adding to $100 million in career winnings but not win?

Rose’s exceptional but skewed golf identity was captured last year at the Tour Championship. Woods won the event, announcing his return to golf’s top 10, as throngs of fans swamped him walking to the 72nd green. But Rose won $10 million that day for the best combined performance over several late-season events.

For nearly four hours Friday, Koepka and Woods simmered with frustration as they missed makable birdie putts. But Koepka finally overpowered the par-5 sixth hole for a two-putt birdie, then knocked down the flag at the tiny, diabolical downhill 108-yard seventh hole, making a birdie putt from inside 5 feet. He had made his move up the board and could use good judgment to par the picturesque but brutal eighth and ninth holes along the cliffs of Carmel Bay.

His lips tighter with each hole, Woods played those seven easy holes in seven infuriating pars. Iron play is paramount here. Pebble Beach, at 7,064 yards, is almost comically short by modern standards. But quirks of terrain, such as gigantic cliffs, and extreme danger beyond 280 yards off many tees create an odd event in which every player concedes “we all end up in the same spot” off the tee.

Then, it’s an iron accuracy contest to see who can hit the ball close to the flag but also keep it below the hole since uphill putts are far easier to make, and much less likely to lead to three-putts, on these bumpy poa annua greens.

Just as Koepka feels that he’s dialing in his game after a shaking week at the Canadian Open, Woods has been betrayed by what was assumed to be a strength at Pebble — the precision of his iron game, which usually includes both distance control and pin-hunting accuracy.

“The greens are still a little slow and bumpy. It’s so important to be below the hole, because above the holes, they’re a little tough to make,” Woods said. “I had a couple chances. But, overall, I kept leaving myself above the hole. Unlike yesterday, when I missed it, I missed the correct spots below the hole.”

For a decade, whenever Woods made the case for shoulda-coulda after his disappointing rounds, eyebrows were often raised. Not now. He’s playing well enough here to fire a low weekend round if he can get his irons dialed in.

But the difference between Tiger’s freshly rediscovered confidence and Koepka’s chest-out self-assurance is touching. Woods usually expresses his optimism tentatively, as if putting his hopes between parentheses with some reference to the quirky moods of his lower back with all its surgical railroad tracks.

Koepka, in contrast, can barely suppress his current self-assurance. Those phrases such as “tremendously better” and “never felt like I had to work hard” after a U.S. Open round at Pebble Beach carry their own aura.

“Brooks is always very focused. Mistakes roll off his back,” Rose said. “He looked rusty in Canada last week. But absolutely, he’s a threat. His name is standing out more than any other [on the leader board].”

With luck, this struggle between Woods, who has been a household name for almost 25 years, and Koepka, who after 24 months in the spotlight is still sometimes mistakenly referred to as “Bruce,” will last for several years.

Often, like Friday, youth will have an inexorable advantage. But, maybe, not always.

For more by Thomas Boswell, visit washingtonpost.com/boswell.