Here's something that might surprise you. Simon Katich is statistically Australia's most successful Test opener of all time. Not Matthew Hayden, not Bill Ponsford. Simon Katich. As Katich shuffled off to the Lord's pavilion having been caught behind for 80, he sat atop the list of averages for Australians who have opened in at least 20 Test innings.

Loping out to the crease to replace Katich was Marcus North. The Australians were hoping Katich's consistency would rub off on North, who stalls on start-up more often than a learner driver. Three balls later, he was heading back from whence he came, bowled for a duck by a high-class inswinger from Mohammad Asif.

How North must envy Katich at the moment. The bookends of Australia's top six share much in common - they are unfashionable left-handers, they learnt their trade on the bouncy WACA pitch and they've each scored four hundreds since the beginning of last year - but consistency isn't one of those traits.

While it's been a feast-or-famine year for North, Katich has been dining out on opposition attacks and scoffing down every last scrap of a score he can find. Australia's opener has been so dependable that when he slashed a typical Katich boundary, an uppish cut through gully to reach his half-century, it meant he'd passed fifty in nine consecutive Tests, stretching back to The Oval last year.

The innings was pure Katich: barely a memorable shot until he'd reached a half-century, then a few boundaries crunched off loose balls, especially against Shahid Afridi. As he crab-walked across his stumps he was opening himself up to a Pakistan attack hooping balls around corners, but aside from a lucky let-off when he should have been trapped on 2, he was Australia's rock on a difficult day.

"There's no doubt that it was a tough day all the way through, given the conditions," Katich said after Australia reached 229 for 9. "At no stage did the clouds break and the sun came through. We knew that it was going to be a hard day out there with the ball swinging around consistently. It would have been nice to get more but at the same time we've got nearly 230 runs in the bank."

None of those runs came from the No. 6. Undoubtedly, North deserves his place in the team after rescuing his career with a century and a 90 in New Zealand, but in addition to his four Test centuries, he has been dismissed for 10 or less in more than half of his Test innings.

His high backlift makes him especially vulnerable to full, swinging deliveries and that's precisely what Asif served up. North was lucky to avoid a golden duck, when he could have been lbw had Pakistan noticed the ball hit pad before bat, and two deliveries later his stumps were shattered by a peach of an inswinger. It was that sort of day for the Australians - get your eye in rapidly or get out even quicker.

"If you get in, it can certainly be a great place to bat because the outfield is quick," Katich said. "Once you get used to the pace you can really get set. But vice-versa, there's always enough happening on days like today where it can be hard for the new guy. I don't think we saw too many poor shots or anything like that."

It's true that North was done in by superb bowling, and his position is rightly not in danger on this tour. However, he is the man with the most to lose if Steven Smith performs with the bat in his debut series. Should Smith convince the selectors that he is a viable top-six option - and with a first-class average of more than 50, it's possible - they will be tempted to push him up and enjoy the luxury of an extra specialist bowler.

Fortunately for North, there were no such signs on Smith's first day of Test cricket. Smith was lbw for 1, one of six Australians who failed to reach double figures. They all needed a little of Katich's consistency to rub off.

Brydon Coverdale is a staff writer at Cricinfo