Unheralded American not afraid to stick his nose where others before him felt it didn’t belong.

After crossing the finish line in third place at yesterday’s Rock ‘n’ Roll San Diego Marathon, Nick Arciniaga stood in the post-race corral with a finishers’ medal around his neck and the semblance of a smile on his face.

“I was hoping for a huge breakthrough performance,” Arciniaga admitted to me just moments after posting a two-minute personal best of 2:11:47. “I ran strong the last 10K and was able to catch a few more guys. I was hoping for better but I’m not going to be disheartened with a two-minute PR.”

Nor does he have any reason to be. Arciniaga’s effort is representative of what’s going right with American distance running these days. His run yesterday was another in a recent line of performances that supports a well-rounded resurgence for the U.S. at the world level. To the unknowing observer, Arciniaga’s result may seem insignificant in comparison to Bernard Lagat’s American record in the 5,000 on Friday night or Chris Solinsky’s barrier-breaking performances this spring, but the significance of being the first American since 1999 to finish in the top-10 at San Diego’s Rock ‘n’ Roll event is anything but small.

“This is huge,” said Arciniaga, who finished eighth at last fall’s New York City Marathon. “One of the goals in U.S. marathoning is to get Americans back in it, back competing with the Kenyans, Ethiopians and everyone, just making sure we have guys up there. Even coming to races like this, not just Boston and New York, and representing is huge for U.S. distance running.”

“If you look at the world level, we just have to start going for it,” said Greg McMillan, coach of Arciniaga and the rest of the McMillan Elite training group in Flagstaff, Arizona. “It doesn’t hurt us to try.”

McMillan believes the ability for American distance runners to overcome pre-existing mental barriers, not physical ones, is the key to making a difference at the international level. And he’s right. For someone like Arciniaga, an unheralded 26-year-old who went into yesterday’s race with modest 2:13:46 marathon credentials, all it took was the chutzpah to stick his nose where others before him felt it didn’t belong.

“It was all about the mentality,” McMillian explained. “We were going into it knowing that we weren’t going to be afraid of anything we saw. Sometimes you need to go into races and do things that you’ve never done before and see how it works out. And I believe if an athlete has a really high fitness level they can go a little quicker than they feel they can. Look, Nick slowed down, but not that much.”

Arciniaga, who ran the first 10K of the race in 29:34 – faster than he’d ever run 6.2 miles before – and hit the half marathon mark less than a minute off his personal best of 1:03:22 for the distance, refused to put himself in a pecking order amongst the all-African contingent of established sub-2:10 runners who surrounded him. Throughout the race, Arciniaga paid little to no mind at the numbers on his watch, even as the going got rough over the second half of the race. He did what competitors do – he competed – an approach not dissimilar to the that of Solinsky, who broke the 27-minute barrier to win the 10,000 meters at Stanford’s Cardinal Invitational at the end of April, and ran under 13 minutes for 5,000 on Friday night for the first time in his career.

“I don’t think we are shooting for any times, Solinsky told competitor.com in an exclusive interview last month. “Obviously, it would be awesome if we can get under 13:00. But the goal is just to compete. If I can finish as close as I can to Bekele, then a time is going to come out of that.”

For Arciniaga, whose “plan was to just sit on the leaders no matter what they were doing,” a top-three finish against a stacked field, two-minute personal best and the respect of his more-qualified competition is what came out of his refusal to be afraid in San Diego on Sunday. It’s this trending attitude of fearlessness amongst American distance runners which wasn’t lost on McMillan as he reflected on the significance of Arciniaga’s performance.

“Our philosophy is to get guys under 2:10 as quick as possible,” McMillan said. “The only way to do that is to go into races and give yourself a shot to do that. It is no longer a marathon run – it’s a race. The way marathons are being run now, we can’t be afraid to go fast in the beginning. I think as more American distance runners change their perception of what’s good, and what they want to run, they’ll start running faster and placing higher. The trend is there – it’s gonna happen. I think Nick’s performance is going to help that.”

That, it will. And for Arciniaga, his third-place performance in San Diego yesterday is just another step along the way in what he hopes will be a continuing trend of brighter medals and bigger smiles.