Williams, making his fifth successive appearance in the championship, said: "I started like a house on fire and I'm normally a slow starter. I won six of the first seven legs but then went to sleep. In the final set I didn't want to get into a tie-break."
Clark won the first leg of the fifth set but Williams held his darts to make it 1-1 and then, helped by a maximum 180, broke his rival to lead 2-1. Then, needing to hold his darts again for victory, he gave Clark no chance to shoot for a double.
The sixth seed, Mervyn King, was beaten 3-2 by Andy Fordham despite having six 180s during the match. Fordham clinched the keenly contested match because of his better finishing, slotting 12 doubles in only 22 attempts.
"I was worried about not finishing well because I know how well Mervyn can score," Fordham said. "But I think tonight was the best I have played in the Embassy, even though I've been a semi-finalist twice."
Phil Taylor may have won his seventh world title on Sunday night when he carried off the Skol PDC Championship for the fifth year in a row at Purfleet, Essex, but for most darts players in this country the 38-year-old from Stoke, who beat the North Cheam news-agent, Peter Manley, 6-2 in the final, will never get the praise due to him until he wins the Embassy title again.
Taylor won the Embassy, the world's richest tournament, in both 1990 and 1992, but a year later became one of 16 professionals who broke away from the British Darts Organisation, the ruling body, to form what is now known as the Professional Darts Corporation.
The breakaway group included seven world champions in John Lowe, Eric Bristow, Jocky Wilson, Keith Deller, Bob Anderson, Dennis Priestley and Taylor, and for a couple of years were superior to the players they had left behind.
However, Wilson has now retired, Bristow is only a shadow of the player he once was and Deller, Anderson and Priestley are not playing as well as they did. Only Taylor and Lowe are still playing good darts. Others, such as Rod Harrington, Shayne Burgess, Peter Evison, Alan Warriner and Manley have come through, but the general standard of play at the Skol event has been lower than the Embassy for the past five years.Reuse content