Gregory was a 6 ft 4 in giant who took a 13-pace approach and bowled with a leaping delivery so violent that mid-off and gully would step back when he ran in. McDonald, by contrast, glided to the crease with what Neville Cardus called 'an air of beautiful malice'. The two had bowled together at Sydney during the 1920-21 series, but the English summer of 1921 was their joint masterpiece.
At Trent Bridge in May, Australia won by 10 wickets in two days; Gregory took 6 for 58. At Lord's in June, McDonald took 8 wickets and Gregory 4 as Australia won by eight wickets. Headingley belonged to both — Gregory 7 wickets in the match, McDonald 5 — and the Old Trafford and Oval Tests were drawn only because of weather and the resilience of Hobbs and Woolley. The aggregate of 46 Test wickets at sub-25 averages had been seen before only from the great Sydney Barnes, but never from a pair operating in tandem at that pace.
The psychological effect was as great as the statistical one. England batsmen openly described being intimidated; Hampshire's Phil Mead said McDonald's away-swinger was 'a thing you could not see properly until it was past you'. The Marylebone Cricket Club was so shaken by the experience that the search for an English answer began that winter — and ended a decade later with Harold Larwood's leg-theory.