Never has the phrase 'schoolboy error' felt more appropriate after Australia batsman David Warner made Pakistan's teenage bowler Naseem Shah pay dearly for a no-ball in the first Test on Friday.
Warner was at his ruthless best as he made the Pakistan attack toil at the Gabba, finishing Day 2 unbeaten on 151 not out as Australia reached 312-1 at the close, 72 runs ahead and in complete control.
But the opener's path to his 22nd century – his first since being banned for ball tampering – was not entirely smooth and he benefited from a reprieve on 56 when he was caught behind off the bowling of debutant Naseem.
The 16-year-old's celebrations of his maiden Test wicket were abruptly halted, however, when TV umpire Michael Gough picked up that he had overstepped the mark and a no-ball was called.
Warner returned to the crease only to endure another scare on 93 when he was inches from being run out by a direct hit from Yasir Shah fielding in the deep.
There was a nervous wait on 99 over the tea break before he finally reached his first Test century in nearly two years with a single clipped off his hips.
While Warner's celebration of his half century earlier in the day had been muted, the left-hander's delight at the hundred was palpable as he leapt into the air in trademark fashion and kissed the badge on his helmet.
"It means a lot," said Warner. "My family and I have obviously had a tough period but that support from Australia here doesn't go unnoticed and I can't thank everyone enough. And obviously my team mates, they've been outstanding."
After the 12-month ban and a disappointing Ashes series in England, where he managed only 95 runs in 10 innings, Warner produced a more measured knock – off 265 balls containing only seven boundaries – compared to the fireworks of some of his previous big scores.
Joe Burns also had a point to prove after being dropped for the Ashes series and it looked like he would join his opening partner with a century of his own.
He fell three runs short on his home ground, however, when Yasir's leg breaks finally earned Pakistan a breakthrough, Burns trapped attempting a sweep and playing on around his legs to depart for 97 and end his 222-run partnership with Warner.
Warner had yet another scare late in the day when an Imran Khan delivery clipped his off stump without dislodging the bails.
"At the end of the day, you've just got to keep working hard and backing yourself," Warner said. "Someone's looking over me and I'm grateful for that.
"Today I was on the receiving end of a bit of luck, which is what you need in a game -- over there [in England] I didn't get any luck at all."
Naseem looked impressive on debut and regularly bowled at more than 145 kilometres-an-hour, but he was guilty of overstepping the mark on a number of occasions, despite not being called by the umpire.
He certainly showed signs as to why he had been awarded his first Test cap at such a tender age with some genuine pace-bowling in his 16 overs, that went for 65 runs.
"[Naseem] won't get a harder Test debut, bowling at the Gabba," Warner said. "He kept his speed up the whole day – he charged in all day, there's a [future] superstar there."
Superstar or not, with Marnus Labuschagne (55) unbeaten and looking in good touch alongside Warner at the close, it could well be another daunting day in the Brisbane sunshine for Naseem and his Pakistan teammates on Saturday.