Spinner Nathan Lyon starred with a match haul of nine wickets as Australia wrapped up the opening Test on Friday with a crushing victory over Sri Lanka before lunch on the third day.

The hosts were bundled out for 113 in their second innings allowing the Australians to seal a 10-wicket victory in their first over back at the crease in Galle.

Lyon, whose five-for helped bowl out Sri Lanka for 212 in the first innings, and fellow spinner Travis Head took four wickets each to send the hosts packing before the morning was over.

It was a huge victory for Australia, who suffered a 3-0 whitewash in Sri Lanka on their last tour in 2016.

"Amazing win. Turning up this morning I didn't think it was going to happen that fast," skipper Pat Cummins said.

"Really proud of the squad. It's really foreign conditions for us."

Opener Usman Khawaja (71) and Cameron Green (77) stood out in Australia's first innings effort of 321 that made them take control in extreme spin conditions.

Green put on crucial partnerships with Khawaja and then wicketkeeper-batsman Alex Carey, who made 45, to handle the spinners with aplomb.

"Players go through their whole careers looking for a method in these conditions, and in his first knock he's found it," Cummins said of the 23-year-old Green who was named man of the match.

"Really happy for him, he was the difference."

Sri Lanka suffered a blow before play began when Angelo Mathews was ruled out due to Covid-19, with Oshada Fernando named his replacement.

Skipper Dimuth Karunaratne started strong, smashing four boundaries in the 17-run first over of the innings off Mitchell Starc.

- Head joins spin party -
But the tables soon turned when Lyon and fellow spinner Mitchell Swepson took charge. 

Lyon got skipper Karunaratne caught behind for 23 after just 20 balls while Swepson trapped Pathum Nissanka lbw for 14.

The leg-spinner then got Oshada caught out in the 12th over as Sri Lanka slipped to 63-4.

Wickets kept tumbling with Sri Lanka's batsmen desperately trying to hit their way out of trouble.

Head, a left-handed batsman and an occasional spinner, struck twice in his first over to claim Dinesh Chandimal -- his first Test scalp -- and Dhananjaya de Silva.

Swashbuckling opener David Warner brought an easy finish to formalities, hitting a four and a six off Ramesh Mendis to bring up the win in four balls.

Earlier in the day, fast bowler Asitha Fernando took Australia's last two first-innings wickets with the tourists adding eight to their overnight 313, for a commanding lead of 109. 

Ramesh Mendis took four wickets while debutant Jeffrey Vandersay took two.

"We bowled well in patches. I think Ramesh bowled really well but the others couldn't support him," said Karunaratne.

The skipper said it was difficult to bat against Lyon, who managed to turn the ball heavily.

"We just wanted to put pressure on him, and play a couple of shots," he said. 

"The approach was really good, the intention was really good, but I think sometimes we took bad decisions."

The third day started early after abysmal weather shortened play on Thursday, with strong winds collapsing a spectator stand.

The second and final Test begins July 8 at the same venue.

Scoreboard
Scoreboard at the end of the opening Test against Australia in Galle on Friday's third day of play:

Sri Lanka 1st innings (212 all out; N. Dickwella 58, N. Lyon 5-90, Swepson 3-55)

Australia 1st innings (overnight 313-8, Cummins 26, Lyon 8)

U. Khawaja c Nissanka b Vandersay         71

D. Warner lbw b R. Mendis                 25

M. Labuschagne c Fernando b R. Mendis     13

S. Smith run out (Dickwella/K. Mendis)     6

T. Head c and b De Silva                   6

C. Green lbw b R. Mendis                  77

A. Carey c Chandimal b R. Mendis          45    

M. Starc c and b Vandersay                10

P. Cummins b Fernando                     26

N. Lyon not out                           15

M. Swepson b Fernando                      1

Extras (b20, lb3, nb1, w2)                26

Total (all out, 70.5 overs)              321             

Fall of wickets: 1-47 (Warner), 2-75 (Labuschagne), 3-83 (Smith), 4-100 (Head), 5-157 (Khawaja), 6-241 (Carey), 7-278 (Green), 8-278 (Starc), 9-319 (Cummins), 10-321 (Swepson)

Bowling: Fernando 8.5-1-37-2 (w2), De Silva 5-0-8-1, Embuldeniya 15-0-73-0 (nb1), R. Mendis 32-0-112-4, Vandersay 10-0-68-2

Sri Lanka 2nd innings

P. Nissanka lbw b Swepson                 14

D. Karunaratne c Carey b Lyon             23

K. Mendis c Swepson b Lyon                 8

O. Fernando c Smith b Swepson             12

D. de Silva lbw b Head                    11

D. Chandimal b Head                       13

N. Dickwella c Labuschagne b Lyon          3

R. Mendis c Khawaja b Lyon                 0

J. Vandersay b Head                        8

L. Embuldeniya lbw b Head                  0

A. Fernando not out                        5

Extras (b10, lb5, nb1)                    16

Total (all out, 22.5 overs)              113

Fall of wickets: 1-37 (Karunaratne), 2-39 (Nissanka), 3-59 (K. Mendis), 4-63 (Fernando), 5-95 (Chandimal), 6-96 (de Silva, 18.5 ov), 7-97 (R. Mendis), 8-108 (Dickwella), 9-108 (Vandersay), 10-113 (Embuldeniya)

Bowling: Starc 2-0-23-0, Lyon 11-1-31-4, Swepson 7-0-34-2 (nb1), Head 2.5-0-10-4

Australia 2nd innings (target 5 runs)

D. Warner not out                         10 

U. Khawaja not out                         0

Total (0 wickets, 0.4 overs)              10

Did not bat: M. Labuschagne, S. Smith, T. Head, C. Green, A. Carey, M. Starc, P. Cummins, N. Lyon, M. Swepson 

Bowling: R. Mendis 0.4-0-10-0

Toss: Sri Lanka

Result: Australia won by 10 wickets

Series: Australia lead the two-match series 1-0

Umpires: Kumar Dharmasena (SRI), Nitin Menon (IND)

TV umpire: Ruchira Palliyaguruge (SRI)

Match referee: Javagal Srinath (IND)