Smith, Carey hit match-defining centuries in Galle

Centuries to Steve Smith and Alex Carey have put Australia on course for a series whitewash of Sri Lanka on an explosive day two of the second Test in Galle.

On a dusty wicket tipped to soon become very tricky for the batters, Smith (120no from 239 balls) and Carey (139no from 156) forged a match-defining, unbeaten 239-run stand that ripped momentum back into Australia's favour.

Australia (3-330) went to stumps 73 runs ahead of Sri Lanka on Friday, having passed the hosts' first-innings 257 around an hour earlier.

With plenty of batting firepower still in the pavilion, the tourists are hopeful they will only need to bat once as they chase a first series win in Sri Lanka since 2011.

"That'd be the plan, but we need to start well (on day three)," Carey said.

"They did it to us last time (in 2022). There's plenty of time left in the game."

Stand-in captain Smith sparked an Australian fightback, coming in when the tourists were in serious trouble at 2-37 and continuing a brilliant resurgence with the bat.

Smith had struggled as an opener to finish the previous home summer and wobbled to begin the most recent one, but now has four tons from his past five Tests.

That includes two centuries from as many innings in the two-match Sri Lanka series.

"It's a pretty good blueprint at the other end to watch and not have to shy too far from his plan, and it worked," Carey said.

It was vintage Smith this time, the straight-laced skipper bringing out his favourite cover drive and even trying his hand at the reverse sweep for one four off Ramesh Mendis (0-70).

It was easy to forget the pitch in Galle was supposed to be difficult for the batters, such was Smith's ability to split the fielders and find the boundary.

"When the ball's hard, there's probably a bit more bounce, a little bit more turn," Carey said of the pitch.

"It will start to fall apart, a bit more traffic on it."

Smith brought up his 36th Test century hitting right-arm finger-spinner Ramesh for four past mid-wicket as shadows began falling on the ground around 4pm.

From the fans on top of Galle Fort, to the Sri Lankan fielders themselves, everyone clapped for Australia's subcontinent master. No Australian has scored more centuries in Asia than Smith (7).

On any other day, Carey would have stolen the show after being shifted up to No.5 for the first time in his Test career and playing a chanceless innings.

Josh Inglis's earlier absence from the field with back soreness forced Australia to shift him down the order, with Carey the man pushed up.

Coach Andrew McDonald would be forgiven for keeping the affable wicketkeeper up higher after he passed his previous Test-high score of 111.

Carey reiterated his status as one of Australia's leading proponents of the sweep shot, and Ramesh proved a favourite victim during his rapid-fire innings.

He popped the finger-spinner's full toss past fine leg with a reverse lap shot for four at one stage, and lifted him over mid-on for six midway through the second session.

Carey brought up his second Test century sweeping a struggling Prabath Jayasuriya (1-107) between the fielders for a four past square leg.

The knock will have silenced any suggestions recent debutant Inglis could be coming for Carey's job as wicketkeeper.

"To have a lead now, going into day three three wickets down, I think that's the satisfying thing, personal milestones aside," Carey said.

Sri Lanka had made a positive start pushing Australia to 2-37 early on, with out-of-sorts Marnus Labuschagne (4) again missing out as part of the early carnage.

With the pitch expected to break up, the home side must have felt ready to rip through the Australian middle-order when Nishan Peiris (2-70) trapped opener Usman Khawaja (36) lbw 15 minutes after lunch.

But Sri Lanka simply had no answers to Smith and Carey, and almost appeared to give up on setting attacking fields when it became clear the duo would chase their lead down.

Sri Lanka wicketkeeper Kusal Mendis held out hope for a fast start on day three.

"We take two or three wickets early and I think we're in the game," he said.