Williams turned professional in 1992 and finished his first season ranked 119th; three years later, he was ranked in the world's top 16 for the 1996–97 season. His first ranking tournament win came in January 1996, when he won the 1996 Welsh Open title, beating John Parrott 9–3 in the final. After failing to qualify for the 1996 World Championship, he won the first ranking event of the new season in October 1996, the Grand Prix, beating surprise finalist Euan Henderson 9–5. In April 1997, he went on to win the British Open, beating Stephen Hendry 9–2 in the final. He also beat Hendry in a "thrilling" final in February 1998, to take his first Masters title, winning 10–9 in a black-ball finish in the deciding frame, after recovering from 6–9 down. At the 1997 World Championship, he was drawn against his coach Terry Griffiths, who was making his last appearance at the Crucible as a player; Williams eventually beat Griffiths 10–9 on the black, but then lost 8–13 to Hendry in the last 16. He reached the semi-finals of the 1998 World Championship, losing 14–17 to Ken Doherty. The following year, at the 1999 World Championship, he made it through to the final and finished the tournament as runner-up to Hendry.