What does your opponent have?

That's a question you need to ask yourself, and here's why: The ability to put an opponent on a hand – or at least a range of holdings – based on his position, his betting and his history, among other things, is one of the most important skills you can acquire to determine whether you have the best hand.

Michael “The Grinder” Mizrachi, one of the most feared players because of his sledgehammer aggressiveness, nailed it while playing the sometimes-tricky hand of bottom set during the L.A. Poker Classic main event at the Commerce Casino in February.

With blinds at $25-$50, Mizrachi saw an early position player limp before raising to $225 with pocket 3s. One of the blinds and the limper called.

The flop came A-J-3, two diamonds, giving Mizrachi a set while putting flush and straight draws out there.

“They both checked to me,” says Mizrachi, a two-time winner on the World Poker Tour. “I bet $500 to represent an ace. I'm going to get called by an ace. I kind of made an overbet on the flop to show I might be bluffing or maybe I had a big hand.”

The blind folded. The limper called.

“He might have a diamond draw or a big ace,” Mizrachi says, showing the early process of putting his opponent on a hand.

The turn came the 5 of spades, putting three cards to a small straight draw on the board in addition to the other possibilities created on the flop.

“He led into me for about $700,” Mizrachi says of the underbet that helped him further narrow his opponent's range of holdings. “I made it about $2,500. I'm thinking he has an ace or aces and jacks. I felt it was aces.”

The river came the 9 of hearts. The limper bet out $1,000. This is a move that players will use in hopes of slowing down an aggressive player such as Mizrachi by giving the appearance of a strong hand when it is really an attempt to limit the cost on the river.

“He was trying to make the hand cheaper,” Mizrachi says. “He didn't want to go $3,000 or $4,000 (which was the amount that Mizrachi could be expected to bet if the limper had checked).”

Mizrachi did not slow down his betting. Instead, he sped it up, raising to $5,500 because he had a great read on his opponent's hand. The limper called, then mucked his cards when Mizrachi showed his set of 3s.

“I knew he had aces or aces up,” Mizrachi says. “He led into me twice to see what I had. I knew I had the best hand. That's why I raised him. It's impossible for him to have deuce-4 (which would've given his opponent a baby straight) because he wouldn't have called such a big bet on the flop with deuce-4.”