Midway through the final lap of the men's 3000m steeplechase at Saturday's Prefontaine Classic, the third meeting of the IAAF Diamond League, a common thought rippled through the 12,000-strong crowd at Hayward Field: who?
As in, who exactly was that Kenyan out front, the guy charging into the final bend with a 15-metre lead over world and Olympic champion Conseslus Kipruto?
The race had been expected to boil down to a head-to-head clash between Kipruto and Evan Jager, the darling of the home crowd in Oregon and an athlete with Olympic and World Championships medals to his name.
But at that point, the script had been well and truly shredded by a 24-year-old Kenyan by the name of Benjamin Kigen, the man with the golden kick.
For Jager, Kigen was a recognisable face, one he'd raced and easily beaten in both Monaco and Brussels last year, a guy to be respected but certainly not feared.
"I've seen him on the circuit but I wasn't expecting him to be the guy today, for sure," admitted Jager. "I thought it was going to be Conseslus and me battling over the last lap."
Kipruto himself was more wary, particularly given the slow pace and his knowledge of Kigen's background.
"I know the guy," said Kipruto, "and I know he can run the last lap very well because he was a 1500m guy."
Kigen's last lap - which he ran over five barriers - was covered in 57.9 seconds.
Truth be told, though, Kigen didn't have as much confidence in himself as others had in him. "I was not expecting it," he said. "This was my first time beating them."
Just 13 months ago, Kigen was still a 1500m runner, but all that changed at a low-key meeting in Thika, Kenya, last April when his manager Juan Pineda watched him sprint to victory in 3:42.9.
He could be a good 1500m runner, he thought, but didn't seem to possess the natural power and pace to truly match the world's best, so they soon plotted a move to the steeplechase.
A native of Baringo County in the Rift Valley, Kigen does not come from an area renowned for producing world-beating distance runners, at least not in the same frequency as places to the west like Eldoret and Iten.
He is a member of the Kenyan Defence Forces and trains in Ngong, a town outside Nairobi that sits at an altitude of 2000m (6,500ft).
There, he works under the guidance of coach Isaac Rono alongside Amos Kirui, the world U20 steeplechase champion who has a best of 8:08.37.
Kigen's transition to the steeplechase was promising, though not paved with success from the outset. He finished second at the Kenyan Defence Forces Championships in his first try at the event in 8:26.6, which secured him a place at the Kenyan World Championship trials last June.
But there Kigen miscounted the laps and with 400m to run, he had yet to make any move believing he still had two laps to run. By the time the bell shook him to life, it was too late and he wound up fourth in 8:20.54.
But his ability became obvious just four days later in Ostrava, Kigen taking victory at the Golden Spike in a huge PB of 8:11.54 before lowering his 1500m PB to 3:36.36 in Madrid.
He then finished fourth in Monaco and sixth at the IAAF Diamond League final in Brussels.
He started 2018 with an indoor 3000m PB of 7:44.77 in Ostrava, though last Saturday's race in Eugene was his first attempt at the steeplechase this year - and what an attempt it was.
ELECTRIC FINISH IN EUGENE
As Kigen soared over the final water jump at full speed - without placing a foot on the barrier - gasps rippled through the crowd at Hayward Field. Though he landed awkwardly at the last, he nonetheless had built an unassailable advantage over Jager and Kipruto, who were left to fight for a distant second, which Kipruto edged in 8:11.71.
Kigen had a good 20 metres to spare when he crossed the line in 8:09.07.
"I dreamt of this and I'm very proud of this day," said Kigen. "This year I have a new training technique so I will do better."
How much better? His time goal this year is to go below eight minutes, which Kigen may well threaten at the upcoming IAAF Diamond League meeting in Rome. Rabat, Budapest and Monaco are also in his plans, and somewhere along the way he will undoubtedly renew his rivalry with Kipruto and Jager.
Far from being upset at his breakout performance, Jager welcomed Kigen's arrival to the big leagues last Saturday.
"It's nice to have another face in contention for the win; it would have got boring if it was the same three guys every year," he said. "Hopefully this puts pressure on everyone else to go after him now and takes the pressure off us. It's fun there's another guy to go after."
And like a true pro, Kigen remains far more concerned with championship performances than fast times. "My main goal is to represent Kenya at the African Championships and race in international races like the Continental Cup," he said.
And now that he's a familiar face, Kigen's rivals will have a new-found respect for his ferocious finish.