The fourth day of the Amateur Championship at Muirfield yesterday was rechristened Black Thursday by the home supporters as all five Scottish hopefuls for the blue riband title fell by the wayside.

Walker Cup man Graham Rankin and James Bunch, conqueror of Justin Rose on Wednesday, tumbled out in the fourth round, while Mark Loftus, Mike Thomson, and Craig Elliot departed a round earlier.

It left the host nation, who have had finalists in five of the past six years, again cursing the jinx of Muirfield, for the last time no Scots featured in the last eight came at the East Lothian links when it staged the 1990 championship.

Rankin, who had looked comfortable in his morning 4 and 2 victory over German Stephan Wittkop, suddenly lost his authority on the greens against leading qualifier Mark Hilton from East Sussex.

Hesitancy, especially over the shorter-length putts, caused the Drumpellier man's downfall, and it came as no surprise when he missed a three-foot putt at the eighteenth to lose. ''If I'd putted just a little bit better I'd have beaten him,'' said Rankin, ''but the worst thing I did was lag my approach putt at the last.''

St Andrews New member Bunch produced a Houdini-like escape in his morning match with American Robert Gerwin, pitching in at the eighteenth to save the match before birdieing the first extra hole from eight feet to win.

However, he faced a stiffer test in the afternoon against South African Trevor Immelman, who lost in last year's final to Craig Watson, the Cape Town player overcoming his own erratic form off the tee to triumph 2 and 1.

''If I expect to win again tomorrow against Mark Hilton I will have to play a lot better than I did today,'' said Immelman. ''But last year I was so serious. I wanted to make sure I came over this time and enjoyed the experience.''

Much-vaunted Spanish teenager Sergio Garcia also progressed to the last eight with a 3 and 2 win over Croydon's Mark Side and will now face reigning English champion Aran Wainwright.

In the bottom half of the draw, Australian Geoff Ogilvy will play Welshman Craig Williams, while Yorkshire's Ben Mason meets Peter Hansson, of Sweden. Results:

Third Round

M Hilton (East Sussex National) beat R Quiros (Spain), 2 and 1; G Rankin (Drum- pellier) beat S Wittkop (Germany), 4 and 2; T Immelman (S Africa) beat G Havret (France), 5 and 3; J Bunch (St Andrews New) beat R Gerwin (USA), at 19th; A Wainwright (Garforth) beat M Harris (Ham Manor), 1 hole; K Ferrie (Alnmouth) beat K Wallbank (Fair-haven), 1 hole; M Side (Shirley Park) beat M Loftus (Cowglen), 2 and 1; S Garcia (Spain) beat S McCarthy (Royal North Devon), 4 and 3.

G Ogilvy (Australia) beat J Wahlstedt (Sweden), 4 and 3; N Pimm (Surbiton) beat G Maly (Porters Park), 1 hole; C Williams (Creigiau) beat J Olver (S Africa), 2 holes; R Vera (Spain) beat C Ravetto (Italy), at 22nd; B Mason (Sand Moor) beat M Thomson (Torwoodlee), 2 and 1; C Rodgers (Royal Mid Surrey) beat E Gibstein (USA), 5 and 3; P Hansson (Sweden) beat M Illonen (Finland), 8 and 7; B Omelia (Newlands) beat C Elliot (Ratho Park), 2 and 1.

Fourth Round

Hilton beat Rankin, 1 hole; Immelman beat Bunch, 2 and 1; Wainwright beat Ferrie, 1 hole; Garcia beat Side, 3 and 2; Ogilvy beat Pimm, 5 and 3; Williams beat Vera, 3 and 1; Mason beat Rodgers, 2 and 1; Hansson beat Omelia, 2 holes.