Now the perception is that Lyon, whose 146 Test wickets is the biggest haul of any Australian off-spinner, gives the tourists the edge. It is hard to argue with that even though Moeen has taken his 33 Test wickets more cheaply than Lyon (at 32 apiece rather than 34).
Lyon has learned on the job; Moeen is still doing so and in this series the Australian's task may be less daunting. Off-spinners prefer bowling to left-handers, especially now umpires recognise all those lbw possibilities. England will probably have seven of them in their team - though Lyon will have to be at his most persuasive to keep the ball in his hand when Stuart Broad and Jimmy Anderson are at the crease.
Moreover, three of those left-handers, Alastair Cook, Adam Lyth and Gary Ballance are not inclined to take the attack to the off-spinner. Even if Lyon does not dismiss them he should be able to keep them quiet.
England should take a positive approach against the spinner - recall how they were becalmed by the relative novice, Mark Craig of New Zealand , during their defeat at Headingley in June - but this is easier for right-handers and they have only three in their first eight batsmen. It may well be that Lyon will not bowl so much to Ian Bell, Joe Root and Jos Buttler in the first innings.
In the second innings this could change. The other factor in this series for the off-spinners of both sides will be the rough outside the right-handers' off-stump later in the game. This will be created by Australia's left-arm pacemen (the anticipation here is that they will play Mitchell Johnson and Mitchell Starc). Land the ball in the rough consistently and the batsmen cannot trust what will happen.
There is more debate over whether Moeen is the right man for the job rather than Lyon, who has finally become unassailable. The inclusion of Rashid squad fuels that discussion though the expectation is that his wrist-spin will be required only at Cardiff in the unlikely event that England opt for a second spinner in their XI.
Moeen's stock off-break is superior to any of his finger-spinning rivals; he imparts more spin than Tredwell or Riley and often manages to get the ball to dip more at the end of its flightpath. What he lacks is experience of bearing the burden of being the frontline spinner, which was highlighted in Barbados in the final Test against West Indies when the ball was turning and expectations of him soared.
However, Moeen performed excellently last summer against India and he needs to remember how. He kept it simple; there was no pursuit of cunning variations of pace or flight, no indulgences with his over-hyped doosra. There were no frills; he did not chase wickets; he bowled relatively quickly and accurately, whereupon Cook kept him on and the wickets somehow came.
It will be trickier this time since the Australians will attack him from the start, a challenging proposition, but one which also gives him opportunities.