Six months ago the 23-year-old Dubliner beat Davis 5-4 in the last eight of the Benson and Hedges Irish Masters, when the former world champion was disqualified for missing a red in the last frame with three consecutive shots.
This latest 5-2 win was far more conclusive and Davis admitted: 'Ken didn't put a foot wrong. He played to a really high standard and knocked me senseless.'
Davis, attempting to capture the Grand Prix title for a record fourth time, won the first frame with a 58 break, but then Doherty, a former world amateur champion, took control and established a 3-1 interval lead.
A run of 54 helped Davis reduce the deficit, but a confident Doherty powered to victory with breaks of 95 and 66. 'This has to be my best win of the season so far,' Doherty said. 'I beat Steve in the Irish Masters, but it was a slightly hollow victory. There can be no doubt about this one.'
In today's 17-frame semi-finals Doherty will meet Terry Griffiths, who continued his consistent recent run with a 5-2 win over his fellow Welshman Mark Bennett. Griffiths, provisionally ranked fourth in the world, is attempting to take his first major title since the 1982 UK Championship.
In the other semi-final Scotland's Alan McManus will meet Jimmy White, who swept past Neal Foulds 5-2 and then declared: 'I'm still only in third gear.'
McManus, the world No 13 after only two years as a professional, beat Nigel Bond 5-3. The 21-year-old Glaswegian transformed a 3-1 interval deficit into another solid performance, allowing Bond just 24 points in the last four frames.
ROTHMANS GRAND PRIX (Reading): Quarter-finals: A McManus (Sco) bt N Bond (Eng) 5- 3; T Griffiths (Wal) bt M Bennett (Wal) 5-2; J White (Eng) bt N Foulds (Eng) 5-2; K Doherty (Irl) bt S Davis (Eng) 5-2.Reuse content