"It was just will power," Siliga, 20, said. "Man, that's all it was. I really needed that third round."
In the first round, Siliga was dazed by a low blow and took a standing eight count. But he took control at the end of the first round with a straight right that hand that stunned Jones.
Both fighters landed plenty of punches in the second round, and the action was fast and furious. Siliga, who is the nephew of former University of Utah football star Sealver Siliga, continued to throw a lot of leather in the third round, while Jones ran out of gas.
Still, Siliga could never drop the taller Jones, who had a four-inch height advantage.
"That dude had a chin on him," Siliga said. "I rocked him a couple of times in that last round, and he wouldn't go down."
The two other Utahns competing in the Tournament of Champions did not fare as well.
Tyrell Rousch of Fullmer Brothers Boxing Gym in South Jordan was overwhelmed by California's Vardan Khachatrian in a 201-pound bout on Monday.
Danny Galloway, the 18-year-old Highland High graduate making his third appearance at nationals, was upset in a controversial bout against Adam Paolino of the New England franchise.
Galloway knocked Paulino down twice in their 160-pound bout, but judges gave the bout to Paulino on points. The decision infuriated several Utah officials who said Galloway dominated the fight and should have won easily.
Boxing continues nightly, with the championship round scheduled for Saturday.