Begin by spreading the deck and having the spectator randomly choose a card.
Take the card back without looking at it and shuffle it to the top of the deck.
Have him pick a number between 1 and 20. If he says 10, place the first 10 face-down cards, one by one, into a new pile.
Then instruct him to, with the new pile of 10, place them one by one into a new pile.
By doing this, he is reversing the order, making the very top card be the first card of the deck, his chosen card.
Tell him to name the card he selected.
As he does so, turn over the top card of the new pile to reveal it is the same card!