It’s an unwritten rule of the England Test side that there must always be one batter whose position in the side is under pressure.

The corollary is less spoken about, that it is rare for there to be more than one player scrapping for their place. As long as someone is struggling more than you, you’ll probably be fine. We can fix the broken window in the front room once the house is no longer on fire.

Right now, Zak Crawley is that man. He has an average of less than 25 opening the batting in Test cricket. He is without a hundred at home in two years. He has batted with a wildly differing array of tempos and played only supporting roles in England’s brief renaissance so far.

All of that, as it happens, is also true of Alex Lees, whose dismissal for four, prodding at an away-nipper from Lungi Ngidi, was his fourth consecutive single-figure score in the first innings. There have been few calls for his head – an advantage of the intense scrutiny that Crawley is under, though if that’s the tactic, it’s by far the wackiest of the McCullum era so far. But Lees will be feeling the heat; he may only have a Test and a half left to extend his first stint in the side.

Lees has entered the post-Strauss twilight zone, the high single-figure to low double-digit caps tally that plenty of England openers make it to, but few leave. Since Strauss’ retirement, England have trialled 18 openers (excluding nightwatchmen and pinch hitters). Five have lasted five or fewer Tests. Four have managed more than 11. Lees is playing his ninth, and only Crawley, of those to play more innings, averages less than his 23.58.

There have been signs of promise in that time. Eight scores above 20 in his first 10 innings. 100 runs in the Trent Bridge Test, which Stokes and McCullum were eager to credit as setting up the carnage that followed. A swaggering half-century to lay the platform for England’s record Edgbaston chase, coming down the track to smear Mohammed Shami third ball, smashing Ravindra Jadeja to pieces, and only departing after a run out for which he was not to blame. Even in the Lord’s hammering, he made the joint-top score in the game’s final innings, fifth out after watching the batting line-up crumble from the other end.

Having come into the team with a county-necessitated, survival-first technique, he has, at times, been able to show that there is another side to his game, that the shots which saw him earn the nickname ‘Haydos’ are still in there.

But he is also yet to fully shake the feeling of a player in the side by default, selected for the West Indies more because England wanted to make a show of a swathe of post-Ashes changes, and then doing enough to keep his place at the start of the next county season. Lees hasn’t exactly been out of his depth as a Test opener. He has, in general, got out to good balls, although Test openers get a lot of those. There is no one glaring weakness. But he’s yet to show why he is the guy, especially in a summer when there have been, for once, a few candidates to suggest they are deserving of a go in the spotlight too.

So what’s next? England are strongly placed after day one, though you would be brave to suggest Lees won’t need to bat again. And whatever happens, England’s backing of Crawley should extend to him, and keep him in the team for The Oval. But beyond that, the picture becomes murkier.

England’s squad to tour Pakistan may be the first with a true McCullum stamp, with a full summer of evidence to examine, a new set of conditions to consider, and several players in contention. If they want a proper aggressor with an enviable first-class record, there’s Ben Duckett. If they want a spin-specialist off the back of a standout season, there’s Keaton Jennings, or even Haseeb Hameed. If they want a redoubtable, proven blunter against a high-quality new-ball attack, there’s Dom Sibley or Rory Burns. Lees needs to show he’s worth sticking with.

Though there have been flickers and sparks, Lees is yet to make that statement score, one that shows why he is the opener England must back. He might only have a few more innings to do so.