"People sort of mentioned maybe I could do it. Normally I really back myself but today I didn't.
"After yesterday I was so disappointed, and then today, I just can't believe it man. I just went.
"Frans Maassen [Lotto Nl-Jumbo sports director] was in my radio, he doesn't get excited about much, and then after halfway he just lit up and I knew was on a good time, and then I just started riding.
"At altitude you can never really go over your limit, and you can never go really deep, and I just held it.
"When I crossed the line, all the cameras were coming, and then I thought: 'maybe I've done something good', and next minute, I'm wearing a yellow jersey."
The 27-year-old paid tribute to his Lotto NL-Jumbo temmates for their contribution to his victory.
"The boys rode their hearts out for me all week," he said.
"No matter what I'm racing for, you've got to respect them and pay them back, so even if I was fighting for the podium, I was always going to be motivated.
"That's just being a professional, that's just being a hungry cyclist; I was always going to go full gas."
Poland's Rafal Majka finished second and American Andrew Talansky was third.