The Holowesko-Citadel rider made the two-man breakaway on a difficult day when the peloton was initially feeling very stingy, sticking it to the line with breakaway mate Ruben Campanioni (Team Jamis) and then winning the two-up sprint on his way to taking the overall race lead.
The stage win in Torrey is a far cry from Carpenter's previously biggest win at the 2014 USA Pro Challenge, where he soloed to the stage 2 victory in Crested Butte. On that day, a solo Carpenter and the chasing peloton were briefly neutralised on a wet and slippery dirt descent off Kebler Pass.
"After I won that stage, I had a lot of friends congratulate me, but I also didn't have any of the validation from other teams or maybe other directors," Carpenter said in the post-stage press conference.
"I think they saw the neutralisation as a bit of caveat, and something that made the race less of a pure race, less of an actual victory," he said. "And today I maybe proved that that's not the case, that wasn't the case. Today I worked my ass off for it and blew everyone's expectations out of the water."
Carpenter and Campanioni escaped after 50km of blistering racing, with Cannondale-Drapac chasing down a lot of the day's early moves as the riders climbed the Hogsback and then headed for the second KOM on Boulder Mountain.
Carpenter won the KOM at 44.7km and then committed to the day once he got a gap and Campanioni bridged up.
"We went full gas up the Hogsback and everything before that," Carpenter said. "We had Travis in the one really dangerous move that had all the teams represented and we were happy with that. But everything kept reshuffling, reshuffling.
"It's funny. Sometimes after a day like that when everyone wants to get in the break, no one gets in the break, and there were only two of us."
Carpenter's teammate, Travis McCabe, who won the field sprint for third, said Carpenter's escape with Campanioni was perfect.
"You could see the last few breaks were just guys rolling off the front," McCabe said. "People were just fatigued and tired because it was so hard. Robin was up there constantly, and it looked like he just put his head down and went. People didn't think anything of it, so it was perfect."
The duo's gap ballooned up to 7:30 by the time they reached the Boulder Mountain KOM with 93km to go, and the pair still had seven minutes when they came off the descent and headed for Torrey, where they faced two 27.2km finishing circuits.
"I definitely started thinking about the victory pretty early on," Carpenter said. "When we had seven minutes at the bottom of the descent, you can do the math and there's the usual rule of a minute per 10km left. We were on it, and then we kept moving ahead of it."
Carpenter and Campanioni held on to finish more than two minutes ahead of the field, and Carpenter admitted in the post-race press conference that memories of his somewhat tainted win in Colorado helped drive him to the finish.
"I said this little bit earlier, but cycling is a funny sport and sometimes you get a little bit – I'm trying to find the right way to say this – but even in my own mind the USA Pro Challenge win kind of had this shadow on it," he said. "Maybe something really did go wrong and I won by accident or something like that. But that's just my own insecurities coming out.
"So coming into the finish line here after riding hard all day and everything going totally normal in terms of race organisation, the cliché words of excited and happy really don't do it. They really don't. I'd have been happy with the stage win, but taking the overall as well, it can't really be described, honestly. It's a combination of a lot of hard work and a lot of determination."
Although Carpenter's 2014 stage win in the 2.HC Colorado race didn't lead to a ride on a WorldTour or Pro Continental team like comparable wins for other riders have, he said he's open to any new opportunities that come his way after his performance on Tuesday.
"I've always said that my number one goal in the sport is just to continue to get paid to race my bike, whether that's here or abroad or anywhere, really," he said.
"That's what I enjoy doing. I love the lifestyle. I love the sport. If the right opportunity comes by and it looks good, then I'll totally take it. You never want to sit back later on and think maybe you didn't take an opportunity because you were afraid of going to Europe or the complicated life stuff that happens afterward.
"But I love my team, I love my teammates and I love the staff. We function really well together and it's been an awesome four years with the Hincapie Holowesko team."
The future certainly looks bright for the 24-year-old from Philadelphia, but Carpenter's current attention is focused 100 percent on his yellow jersey and what it will take to defend it on Wednesday. Stage 3 will take riders over Mt. Nebo, the highest peak in Utah's Wasatch Range.
"It's going to be a super hard climb tomorrow, but I think we'll try and defend it because there is a distinct possibility I'll be able to stay in that group," he said. "I've been climbing really well this year.
"But I think mostly we're just proud to have taken the jersey in such a decisive fashion."