Smith's snub of Lyon pays off at MCG

For a brief while in the Boxing Day Test, Nathan Lyon's most vocal support was coming from the commentary box rather than behind the stumps.

Wicketkeeper Matthew Wade's cries of "Niiiiice, Garry" have become the soundtrack of Lyon's summer and a crowd sensation all in one.

And with Lyon taking 3-21 in a brilliant spell before tea with the match up for grabs on day five, it seemed inevitable they would ring out across the MCG louder than ever once Pakistan resumed at 5-91.

But captain Steve Smith instead turned to frontline quicks Mitchell Starc and Josh Hazlewood to finish the job.

The decision proved inspired, with Starc taking 4-36 to rip through the tail and hand the hosts an unassailable 2-0 series lead.

But it almost caused a riot among Australia's former cricketing greats.

"It's like Steve Smith doesn't want him to take wickets," a fuming Shane Warne said in the Nine Network commentary box.

"There's no logical reason why he's not bowling.

"Look at that, 3-21 off 10 (overs). He's got Australia into this game. I just don't understand it."

Warne wasn't alone, with former Test captain Mark Taylor and Michael Clarke both making it clear they felt Smith should have gone to Lyon.

"Why is @NathLyon421 not bowling after the tea break?????????????," Clarke posted on Twitter.

But Starc soon delivered for his captain, taking the crucial wicket of Sarfraz Ahmed before cleaning up the tail.

Speaking after the match, Smith said he considered throwing the ball to Lyon but had sensed an opportunity for Starc to strike.

"(Lyon) was bowling beautifully, there's no doubt about that," Smith said.

"But the ball was still hard and it started to reverse ... it brings in both sides of the bat and I thought there was an opportunity for that straight up, so that was my plan."

All ended well for Lyon, whose brilliant spell has guaranteed he will retain his spot for the third Test in Sydney.