The seven time Tour-de-France winner crushed the Ironman 70.3 Florida bike course for a race-best 2:01:13 bike segment that was a huge 10 minutes 30 seconds ahead of the next racers.
He topped off the bike with a 1:15:56 half marathon split to win the race ahead of second place finisher Maxim Kriat of the Ukraine.
"Despite feeling really good, I just tried to stay within myself," Armstrong said after the race.
"I followed the GPS to make sure that I was on my pace, which was 5:45-5:50 and didn't try to go any quicker."
Armstrong attributed his success to the fact that he finally got the nutrition right in Florida.
"I felt pretty good I must say. Think I finally figured out the nutrition component which has been dogging me," he tweeted after the race.
On the women's side of the race it was an all America podium with Jessica Jacobs taking the win in a time of 4:24:30.
Top 5 Professional Men
1. Lance Armstrong (USA) 3:45:38
2. Maxim Kriat (UKR) 3:56:56
3. Francesco Goday (ESP) 3:59:45
4. Andres Castillo (COL) 4:01:08
5. Mauro Cavanha (BRA) 4:02:04
Top 5 Professional Women
1. Jessica Jacobs (USA) 4:24:30
2. Jennifer Tetrick (USA) 4:26:09
3. Amanda Stevens (USA) 4:28:19
4. Nina Kraft (GER) 4:28:43
5. Tamara Kozulina (UKR) 4:31:14
Photo Credit: Ironman