Life as an understudy isn't easy.
Consider the example of Jimmie Nicol. Nicol, it might be remembered, was a Beatle for about 10 days in 1964. With Ringo Starr suffering from tonsillitis, Nicol, an accomplished session drummer, was drafted in to ensure the band fulfilled a raft of touring commitments. By all accounts he acquitted himself very well, too.
But it was never going to make any difference. After eight shows, a revitalised Starr returned. Nicol faded into the background with only an inscribed gold watch to convince sceptics in the pub of the days when he was fab.
Time will tell whether the same thing happens with Sam Billings. Billings batted beautifully for a while on Friday night. He not only recorded his maiden international century but, for a while, took apart Pat Cummins - the world's No. 1 ranked Test bowler at present - in thrashing him for 39 from just 22 balls.
And while England fell 19 runs short, the sense remained that, had a couple of the other batsmen been able to stay with Billings just a little longer, he might have pulled off something really quite incredible. He, at least, believes he had Australia rattled at one point.
There were moments in Billings innings it seemed an uneven contest. At one end, Jonny Bairstow was being beaten like a snare drum; at the other Billings had 11 from 32 balls. "They reminded me I was 11 off 32 pretty consistently," he said of Australia's fielders. England were light years behind on the comparative run rate.
"At that point in time we had zero chance," Billings said. "I felt terrible as well. I wasn't fluent at all. But then you look at the other end and Jonny is struggling as well and he's one of the most fluent openers in world cricket. No one really got going.
"But you could see Australia's mindset definitely change when we started to get that partnership going. The energy all of a sudden went from very positive to just a slight more intensity and thinking that we are getting ourselves back into the game.
"Who knows, if Jonny and I had batted for another five overs; if Moeen Ali and I could have got a bit of a partnership together… Yes, it was a huge ask. But in that situation it's a matter of trying to take the game deep and give us some sort of chance."
Despite the result, Billings demonstrated many of the attributes England are looking for in their players. For a start, he was resilient. From a position of near hopelessness - chasing what would have been a record total to win an ODI at Emirates Old Trafford, England limped to 22 for 2 after 10 overs, their lowest score at that stage of a home ODI since 2006 - he took the game into the final over.
Secondly, he was adaptable. After soaking up pressure towards the start of his innings, he showed an ability to accelerate and damage opposition that underlined the impression he could enjoy a decent career at this level. Anyone who can straight drive and ramp Mitchell Starc, who is probably within the best half-dozen or so middle-overs bowlers in the history of this format, can really play. He's a decent player of spin and one of England's bravest and most athletic fielders, too. There's a lot to like.
But Billings' problem - and it really is a two-pipe problem, as Sherlock Holmes might have put it - is that he's the stand-in for Ben Stokes. And that's an issue, as Stokes might just be the finest cricketer England have had this century. So just as Dawid Malan is struggling to displace Jonny Bairstow or Jason Roy, so Billings isn't going to force his way into this side - any side - ahead of Stokes. And he's not going to force his way in ahead of Jos Buttler or Eoin Morgan, either.
But he could force his way into the T20 or even the Test side. With Buttler set to bat at the top of the order in the shorter format, there might just be a vacancy as a floating middle-order batsman alongside Morgan and Stokes. And with two T20 World Cups - in theory, at least - to be staged in the next couple of years, it seems a worthy aim.
The role of middle-order T20 batsman is desperately tough to nail down. You have, in essence, very few balls in which to impress and almost no opportunity to play yourself in. So it's maximum risk for, on a personal level, minimum reward. Billings' statistics demonstrate this: he's played 30 T20Is and faced more than 25 balls in an innings only once. The other 24 times he has either not batted at all or faced 11 deliveries or fewer.
"Ben Stokes isn't here and I don't think, however many runs I get, that I'll keep that spot," Billings said of his ODI role. "All I can do is stake a claim. Especially building towards the T20 stuff. There is a slot in that late-to-middle order. Hopefully this will keep pushing my case in that format. [Loss of] form and injury - as I found out the hard way - can happen. As long as you are putting yourself in the right position to be the next cab off the rank, you never know when these opportunities will arise."
The "hard way", as he puts it, came last year. After an excellent innings of 87 in a T20I in St Kitts, Billings looked well-placed to be the reserve batsman in the World Cup squad. But then he sustained a serious shoulder injury which ruled him out and saw James Vince selected instead. Vince not only played in three games but was on the pitch (as substitute for Mark Wood) for one of the most dramatic moments in the history of English cricket, that Lord's Super Over. Now aged 29, the sense that time may be running out must be gnawing Billings harder than ever.
"Last year was easily the toughest of my career," Billings said. "Missing out on the World Cup squad and that whole experience. It was a really tough experience [but] I've stayed pretty philosophical about it. The white-ball batting depth at the moment in this country is pretty phenomenal. Of course it's frustrating.
"But Joe Root said to me yesterday, the amount of cricket I've played, I'm more like a 26-year-old. Dan Lawrence is six years younger than me, but has played more first-class cricket than I have. I'm still improving as last night showed.
"I'm in a really good place with my technique that could obviously transform to the longer form of the game as well. Ollie Pope is out [injured] for a little while and that middle order spot [in the Test team] might be vacant."
Indeed, it might. So perhaps, if Billings can repeat such performances, he will look back on this period not so much as an understudy but as an apprenticeship. The best could still be ahead of him.