It was the hardest stage of the Tour of the Gila, but Armstrong and his teammates Levi Leipheimer and Chris Horner passed the test. The Astana riders, who entered the five-day event as independents, used the tour as a tune up for the upcoming race in Italy.
Armstrong said he feels good enough to be a contender for some stage wins in Italy but that Leipheimer has the best chance for an overall win.
"The first priority is to protect him and make sure that he fulfills his potential there," the seven-time Tour de France winner said. "It would be an amazing thing for an American to win the tour of Italy again. I'd be pleased to be there and help."
Leipheimer won the Tour of the Gila on Sunday after finishing first in two of the early stages and coming in third behind Armstrong in the last stage, dubbed the Gila Monster. Armstrong moved up in the overall classification from fourth to second after Sunday's stage.
The Astana riders, who were wearing the kits of Armstrong's Mellow Johnny's bike shop, moved to the front of the peloton as it closed a gap of more than three minutes that had been built by a breakaway of 11 riders in the first 40 miles of the stage.
At the start of a 7-mile, 1,600-foot climb to Copperas Vista, the Mellow Johnny's riders caught the lead pack. With Horner in front, he and Leipheimer positioned to get Armstrong the stage win.
It looked like it was going to happen until the last 500 meters.
"I didn't know the finish. I didn't know it was so much uphill. I thought maybe it would flatten out and there'd be a high-speed sprint... but it kept going up," Armstrong said.
He was caught behind the wheel of another rider and had to go around. By that time, Leipheimer was ahead with first-place finisher Philip Zajicek on his wheel.
"When I finally got back to the wheel uphill, I was cooked," Armstrong said.
Astana general manager Johan Bruyneel said the plan Sunday was for Armstrong to win the stage.
"It didn't really play out like we wanted it to be," he said. "It's a little disappointment he didn't win the stage, but overall I think it was a good race for the team."
It's also been a few good days for southwestern New Mexico. Several thousand people crammed downtown Silver City on Saturday to watch the criteriums and hundreds of people lined nearby Pinos Altos' main street to watch Sunday's finish.
Leipheimer, who also won the Tour of California and the Vuelta of Castilla and Leon this season, said he's proud to grab another title with the Tour of the Gila. He said events like the Gila go a long way in igniting interest in American cycling.
For the fans in New Mexico, Armstrong had one last message on his Twitter post: "Thanks to everyone here for showing us a great time. This is a great (and hard!) race."
The riders are now on their way to Italy to be tested yet again.
"With the Giro, we'll just take it day by day, kilometer by kilometer and just sort of have fun and do our best," Leipheimer said.
There is a long list of Italians who will also be vying for the Giro's pink jersey, he said, including former winners Ivan Basso and Danilo Di Luca and Franco Pellizotti.