He and Farah race as one team and for one coach, but for two nations. Their stunning and beautifully run performance here shook the ground inside and outside the Olympic Stadium.
Rupp, a 26-year-old from Portland, became just the third American, and first since Billy Mills won gold in 1964, to win a medal in the 10,000 meters.
For Farah, born in Somalia but raised in London, the victory was part of a remarkable one-night spree for the team from Britain. Within 30 minutes, Farah won the 10K, Jessica Ennis won the gold in heptathlon, and Greg Rutherford won the long jump.
Rule, Britannia, indeed.
"I saw Jess carrying the flag, and I knew she won the gold," Farah said. "As I came through the tunnel, the atmosphere when you walked into that stadium was something else. It was like someone gave you 10 cups of coffee. I was shaking, almost. I had that feeling walking into the stadium. I felt like, wow, I have to do something."
Both men traveled much farther than 10,000 meters to reach that podium. Farah's childhood took him from Somalia to Djibouti to London. His training took him from London to Kenya, where he trained with the African runners who dominate distance running, to Oregon, where he trains with Rupp under Salazar.
As an American distance runner, an endangered species since the 1980s, Rupp may have had an even longer journey. He has worked with Salazar since he was in high school and was there when Salazar and Nike created Project Oregon - an effort dedicated to getting Americans and Brits back on the medal stand for distance events.
"This has been a long buildup," Rupp said. "I remember talking about this with [Salazar] in high school. He set this audacious goal to put Americans back on the medal stand in distance races. He said, 'It's going to take a long time, and we're not going to take any shortcuts.' There have definitely been some bumps in the road along the way. He takes a long-term, gradual approach, and that really paid off today."
Salazar, three-time winner of the New York Marathon in the early 1980s, said he fully expected both Farah and Rupp to deliver in this race.
"I'll be honest," said Salazar, who was wearing a 2011 Penn Relays cap. "I thought we were going to medal. I thought we could go 1-3. I believe Mo is the best distance runner in the world, and I know Galen is just a step behind. Galen just knew, 'If I stay close to him, it's going to be pretty hard for more than one guy to slip in between us.' Today, nobody could."
The plan called for Farah and Rupp to work together, maintaining as easy a pace as possible without allowing too big a gap to form if someone broke away. Midway through, Rupp said: "I was getting a little antsy. Some of those guys were starting to surge. I was wondering if I should go, and Mo kind of tapped me on the shoulder and said everything's fine, they're going to come back."
Once the pack reached the final lap, Farah said: "It was every man for himself."
"We felt they could outsprint anyone in the race," Salazar said. "We didn't care if it was a fast pace, a slow pace or whatever. They weren't going to try to win it until the last 400, even the last 200 meters."
It worked perfectly. Farah took off during the final straightaway. Rupp followed. As Farah crossed the finish line in 27 minutes, 30.42 seconds, he did two things in quick succession: He raised his arms, and he looked quickly back. Rupp was right there in 27:30.90, and the expression on Farah's face as he realized they'd finished 1-2 told the whole story.
"To win this in my hometown, along with my best friend, it's just the happiest moment of my life," Farah said.
"I still can't get my head around it," Rupp said.
Such a simple race plan, such a brilliant race.
Contact Phil Sheridan at 215-854-2844 or firstname.lastname@example.org, or follow on Twitter @Sheridanscribe. Read his blog, "Philabuster," at www.philly.com/philabuster. Read his columns at www.philly.com/philsheridan