LAS VEGAS — A 21-year-old Michigan poker professional who chose cards over college won the World Series of Poker main event in Las Vegas early Tuesday, winning $8.55 million and becoming the youngest player to win the tournament in its 40-year history.

Joe Cada of Shelby Township, Mich., turned over a pair of nines early after 46-year old Darvin Moon called his all-in wager with a suited queen-jack, setting up an about-even race for most of the chips on the table.

But a board of two sevens, a king, an eight and a deuce didn't connect with either player's cards and gave Cada the win.

"I ran really well and I never really thought this was possible," Cada said. "It was one of those dreams and I'm thankful it came true."

The hand abruptly ended a final table that saw Moon, a logger from western Maryland, bounce back to a dominant chip lead after being down 2-1 in chips to start the night.

"I only play good when my back's against the wall," Cada said.

Cada broke a record for the tournament's youngest winner set last year by Peter Eastgate of Denmark. Cada is 340 days younger than Eastgate.

The record was previously held for two decades by 11-time gold bracelet winner Phil Hellmuth, who posed for pictures with Cada after the win.

When asked what's next for him after reaching the pinnacle for poker so early in his career, Cada said: "To win it back-to-back."

Moon and Cada traded the lead several times in 88 hands spanning nearly three hours of play, with one 20-minute break.

Moon erased Cada's lead in 12 hands, revealing a pair of queens during a showdown to rake in a pot worth millions of chips. Cada shook his head after he lost and briefly stood up from the table, walking over and chatting with two of his supporters.

After some chip-shifting, Cada was ahead by less than 4 million chips after 52 hands, with 194.8 million chips in play.

But Moon stormed to nearly a 100 million-chip lead after the break, visibly frustrating Cada and leaning on him to make tougher decisions.

Fortunes changed when Moon pounced on a board with two 10s, a nine and a five to put Cada's entire tournament at risk. After a sip of bottled water and several minutes of thinking, Cada called the bet and flipped over a nine for a pair.

Moon held a straight draw but didn't hit his hand on the river, giving the lead back to Cada and drawing roars from the crowd.

"I should have went all-in on the flop. He made a phenomenal call," Moon said. "That's why he's the champion."

Moon won $5.18 million for second place.

The players traded chips atop a table with a stack of cash and a gold bracelet on its felt, and in front of nearly 1,500 screaming fans in a capacity crowd at the Rio All-Suite Hotel & Casino.

Their tug-of-war ended an epic tournament that began with 6,494 players in July.

After a 115-day break, Cada and Moon endured more than 14½ hours through 276 hands at the final table on Saturday and early Sunday, when they outlasted seven others to make it to heads-up play.

Moon entered with slightly fewer chips than he started the nine-way final table with, making him an underdog in chips for the first time all tournament.

Unlike Cada, who said he regularly plays about a dozen tournaments at a time online or three at a time in heads-up cash games, Moon hasn't played a single hand of online poker. He doesn't even own a computer or have an e-mail address.