He won the first ranking event of the 1988–89 snooker season, a 12–6 victory over White in the International Open. During the same match, Davis became the first player to make three consecutive century breaks in a major tournament. In October, he won the Grand Prix final 10–6 against Alex Higgins and held the World, UK, Masters, Grand Prix, Classic and Irish Masters titles simultaneously. His four-year unbeaten run in the UK Championship ended in December with a 3–9 semi-final loss to Hendry. Davis did not win another major title until the 1989 World Championship, where he beat Hendry 16–9 in the semi-finals before the most decisive victory in a world final of the modern era: an 18–3 win against John Parrott, for his sixth world championship. He retained the Grand Prix in October, beating Dean Reynolds 10–0 in the final – the first whitewash in a ranking-event final. By the end of the 1980s, Davis was snooker's first millionaire.