"I'm struggling right now," he said, sucking for air and gazing wayward just seconds after crossing the Erlanger Chattanooga Marathon finish line Sunday morning.
The 29-year-old husband and father who is battling stage 4 brain cancer finished the race in 1:41:07. That works out to a 7:44-mile pace for the 13.1-mile run.
He ran 31 seconds faster than his pace goal, enough to earn him a first-place finish among his 40 co-workers from Bellhops, the local startup moving company where Sexton works.
Sexton completed most of his training near his Signal Mountain home, running 11 miles on his longest training run with a pace time of over eight minutes.
"But I knew this was a flatter course," said Sexton, who admitted he hoped to best his stated goal of an 8:15-mile pace.
Sunday's results didn't come easily, though.
His running companion, Ali Al-Chalabi, began to notice Sexton hurting as he neared the final stretch.
"Around 11 miles or so, I was shouting at him," Al-Chalabi said. "You need some motivation. I could tell he was starting to hurt a little. But he persevered."
"I was really just thinking, 'don't die now,'" Sexton added.
The Knoxville native and University of Tennessee graduate was given an initial prognosis of 15 months to live when he was diagnosed with glioblastoma last June. Running the half marathon, he said, was a metaphor for learning to endure pain over a long period of time.
"I'm really just blessed for God giving me this opportunity and the chance to run this race when not even a year ago I was getting brain surgery," Sexton said. "I'm really honestly just blessed to have this opportunity and to share my story."
Sexton was scheduled to begin a five-day round of a pill form of chemotherapy Sunday night after the race, which may have just been the first in his new distance running career.
"My dad surprised me with a trip out to Napa to do the Napa-to-Sonoma half marathon," Sexton said, referencing the prominent California event. "But that's not until July.
"I'll find something to run between now and then."