"At three-nil down, all right isn't good enough," he says. "There have been times when I feel I've belonged, but I haven't made the scores that are required in Test cricket.
"In the first two games, we made 50s and they made 100s. And in Perth we made hundreds and they made double-hundreds. I think that's been the difference and that's the frustrating thing as we've done a lot of good things in patches but just as it felt we were close to getting on top they've managed to get a breakthrough.
"Personally, it's been pretty disappointing because I've made starts in a lot of innings."
You can understand why the question was asked, though. Stoneman has, like Craig Overton and Jonny Bairstow, done all right. Dawid Malan and James Anderson might even have done a bit better than that. Stoneman has taken on the bowlers at their freshest and the ball at its hardest and he has easily out-performed the man with the most runs in the history of Test cricket as a regular opening batsman. Stoneman, averaging 32.16 in the series, has reached 27 in four of his innings (and made 18 in another) but never gone beyond 56. He has, not unlike Michael Carberry in the 2013-14 Ashes, who averaged 28.10 with a top-score of 60, done the hard work but not capitalised.
Part of the problem when confronting this Australia attack is 'the hard work' never ends. They have been relentless. So well has Nathan Lyon supported them that despite 'only' having a three-man pace for the first two matches of the series they always had, as Stoneman puts it "a guy coming in relatively fresh." So batsmen can't just weather the storm in the hope of calmer waters to come. The storm never ends.
The barrage that Stoneman has faced all series reached a peak in Perth. Spurred on by the pace and bounce in the wicket, the Australia seamers unleased a terrific assault upon him which saw him struck on the helmet, survive several near misses as the ball ballooned to safety after it his gloves or the splice of his bat and eventually caught behind after a slightly controversial decision by Aleem Dar, the TV umpire, to overrule the on-field 'not out' decision.
Stoneman admits he has never experienced sustained ferocity of the like. And he admits that, despite being married to an Australian, he now has a "different take on the population" having been subjected to the verbal assaults that seem to come with the territory. But so confident was he that he hadn't hit - or been hit on the glove - by the ball that dismissed him in the first innings that he was going to review had he been given out by the on-field umpire. "I thought I was quite safe," he says. "I thought it clipped the grill of my helmet. I was going to review it myself if it had been given out."
"I've not faced an attack before where they have three guys capable of cranking it up to the levels they do," he says. "And the wicket in Perth created bounce that was a lot steeper than I've ever experienced.
"There were balls where I was picking up the length fine. But I was perceiving the level of contact to be chest height, which I would happily get in behind and ride, but they just kept climbing and I ended up splicing them in front of my face. I guess it's all part of the learning curve in my first time at the WACA.
"The general experience has - despite the results - been amazing. The atmosphere is brilliant, albeit very one-sided. They're not the nicest people when you're playing against them. It gives you a different take on the population when they've got a few ales down their neck. It's been great to be a part of, it's just very disappointing about the results."
Part of the problem is that Stoneman has no counter punch to the short ball. He has concluded - not without some logic - that the hook and the pull are not percentage strokes in such circumstances. But that leaves his options as ducking and attempting to ride the bounce and the bowlers no concern that their barrage might concede runs and relinquish any pressure. Whether it is an issue that will ever bother him again - the WACA is almost unique, after all - remains to be seen, though, and he doesn't feel his technique requires major adaptation.
"I find that, against the new ball, with the extra pace and bounce in the wicket, that staying on top of the ball is hard work," he says. "And there are big fields, too. When they are men out in the deep, you're not going to clear them.
"If they're coming into their fourth and fifth spells, that might be the time to take them on [with the hook], but I'll probably just try and get my head out of the way better next time."
So how does he register the big score that might contribute to a better result for England? How do they win in Melbourne?
"We have to repeat the good things we've done for longer," he says. "You hear the greats of the game or the top coaches talk and it's all about repeatability.
"Look at Steve Smith in this series and he just kept repeating what he did. Any plan we had, he worked out how he was going to counter it or absorb it. He's shown levels of patience and good attacking instincts and he just repeats. It's simple, really."
The difference between Smith's challenge and Stoneman's is significant, though. While Smith's patience and discipline have been tested, Stoneman's courage and technique have been. So while England are putting the ball in good areas hoping Smith will make a mistake, Australia are hurling it at Stoneman in the knowledge that even the semblance of indecision can bring them a wicket. The concern is that, by the time Stoneman reaches 50, he is mentally spent.
What he has been, though, is phlegmatic. Impressively, so. And brave. Most of the time, at least, you cannot tell if the previous delivery has beaten him, him or been hit for four. He gets into line and plays it on merit. He looks to be the answer to England's almost endless search for an opening partner for Alastair Cook. Instead, it may be we are talking of the need to find an opening partner for Stoneman before long. Ten innings for Cook without reaching 40 - and nine of them haven't reached 25 - isn't sustainable.
The motivation for Stoneman and England now is to prevent the indignity of a whitewash. The Ashes may have gone but, with the two post-Christmas Test featuring huge crowds (it is likely that none of those involved will play in front of a bigger crowd than on Boxing Day at the MCG), there should be little sense that the series is winding down. Besides, quite a few of this England side have their places in the side to secure.
"The Aussies are going to be coming at us looking for 5-0," Stoneman says. "So there's the first thing we've got to stop. I don't think any Ashes cricket is going to be meaningless cricket. They're not going to be serving up half-volleys for fun because they're won the series, that's for sure, so we've got to go out and play our best.
"It hurts a lot right now. But knowing the support we have and the people who are coming out to watch and get behind is a real motivating factor. It's kind of irrelevant how things are judged from my point of view I want to go out there and do my best for England."
Whatever happens, England will need more than half their team performing 'all right' if they're to win a game from here. Stoneman knows it.