Khawaja hits 200 before Aussie bowlers strike in Galle

Usman Khawaja has played the greatest innings of his Test career to help Australia tighten the screws on Sri Lanka in a series opener fast slipping away from the hosts.

Khawaja (232), milestone man Steve Smith (141) and debutant Josh Inglis (102) feasted in Galle on day two as Australia declared on 6-654, their largest total for any innings on the subcontinent.

Sri Lanka (3-44) then lost three wickets within an hour and could have been four down had substitute fielder Nathan McSweeney held onto Dinesh Chandimal's edge above the slips.

Australia were 610 runs ahead at stumps on Thursday, with Kamindu Mendis (13no) and Chandimal (9no) unbeaten.

"It was a brilliant start," Inglis said.

"It always helps when they've obviously been out in the field for a long time so they'll have heavy legs.

"The wicket's obviously starting to take a bit more spin now, it's wearing, so hopefully start well tomorrow, take a couple early."

With victory teetering out of reach, Sri Lanka have shifted into survival mode.

"Australia's got a mammoth on the board so I don't think we need to focus on the total much," said legspinner Jeffrey Vandersay.

"Just keep batting and bat long. That's as simple as it can be."

Opening the bowling, left-arm off-spinner Matthew Kuhnemann (1-26) struck to dismiss a nervy Oshada Fernando (7) lbw in his first over since dislocating his thumb a little more than two weeks ago.

Spectacular catches from McSweeney in the slips and Travis Head at short leg pushed Sri Lanka into a world of hurt and, respectively, handed Mitch Starc (1-10) and Nathan Lyon (1-7) early scalps.

Earlier, veteran opener Khawaja silenced the critics who came out in force during a tough summer, and surely extended the lifespan of his long career with his first Test double hundred.

Khawaja was dropped twice and would have been out caught behind if Sri Lanka had used a review on day one, and was nearly run out at the non-striker's end when he strayed from his crease early on Thursday.

His fortune finally ran out in the second session, edging Prabath Jayasuriya (3-193) to gloveman Kusal Mendis and immediately walking.

Khawaja left in good company, Donald Bradman being the only other Australian to reach 200 runs in a Test innings after his 38th birthday.

Cramping prevented him from fielding when Sri Lanka made it to the crease late in the day.

Once lambasted for his track record against spin, Khawaja reverse-swept often and effectively across the 352 deliveries he faced on a pitch offering limited bounce.

He found the gap between fielders throughout the innings, and passed his previous high score (195no) by hitting Jayasuriya past cover for four in the first session.

The veteran raised a fist to the air as he snuck a single at mid-off to reach 200, kneeling on the ground and kissing the turf.

It was a slightly smaller Galle crowd to the one that attended day one to see Smith pass 10,000 runs, but the punters nevertheless rose to applaud Khawaja under the historic city's clearest skies of the week.

Inglis vindicated his selection as a specialist batter at the expense of teen sensation Sam Konstas, speeding his way to triple figures from only 90 deliveries.

Only India's Shikhar Dhawan (85) has reached a century faster on Test debut.

Inglis's aggression and proficiency against spin were on full show as he became the first Australian debutant to score a century since Adam Voges in 2015.

"It probably hasn't sunk in yet but nice to put the team in a really strong position," Inglis said.

A six from Vandersay (3-182) over long on was a particular highlight, before Inglis edged Jayasuriya to cover.

After opting not to review two would-be wickets on day one, the hosts finally figured out the DRS and sent an lbw shout upstairs to end Smith's blistering innings.

Smith raised his bat to the crowd at the end of an innings that could have finished on one had Jayasuriya held on from his own bowling.

Instead, Smith continued to wreak havoc on day two and passed Sunil Gavaskar into 13th place on the all-time Test run-scorers list with a six over long on.

Smith has now scored 10,140 runs in the baggy green.