Shiel damaged his knee at an early stage but did not come off until the second half when he was replaced by Hastings. But Hastings, the Watsonian centre, lasted only 12 minutes before receiving a deep cut on his left knee that needed immediate stitching and, of the two, he must be the most doubtful for Saturday's second Test against New Zealand.
"It is very disappointing to lose both outside centres," the team manager, Jim Telfer, said. "Scott caught his knee on a stud in a tackle."
One player who stood out against the scratch side was the flanker Peter Walton. The Newcastle player capped a good performance with two tries, a feat also achieved by wingers Tony Stanger and Ken Logan.
Scotland's other try-scorers were Gary Armstrong, Nick Broughton, Rowen Shepherd and captain Craig Chalmers, who with five conversions and a penalty finished with 18 points.
Shiel, until he retired injured, had contributed hugely to the Scots' ball movement among the backs, and the Scots were also well served by the link work of the flanker Nick Broughton, who was frequently involved in the attacking moves.
South Island: Tries Connolly, McDowell; Conversion Dempster; Penalties Dempster 2; Drop goal MacDonald. Scotland: Tries Logan 2, Stanger 2, Walton 2, Armstrong, Broughton, Chalmers, Shepherd; Conversions Chalmers 5; Penalty Chalmers.
SCOTLAND: S Lang (Heriot's FP); A Stanger (Hawick), G Shiel (Melrose), R Eriksson (London Scottish), K Logan (Stirling County); C Chalmers (Melrose, capt), G Armstrong (Newcastle); T Smith (Watsonians), G Ellis (Currie), P Wright (Boroughmuir), S Campbell (Dundee HSFP), S Murray (Edinburgh Academicals), P Walton (Newcastle), E Peters (Bath), N Broughton (Melrose). Replacements: R Shepherd (Melrose), S Hastings (Watsonians), A Nicol (Bath), G Weir (Newcastle), B Stewart (Edinburgh Academicals), K McKenzie (Stirling County).