Travis Head's dashing century was the centrepiece of an Australia fightback against India on the opening day of the World Test Championship final at The Oval on Wednesday.

Australia were in a commanding position on 327-3 at stumps after losing the toss, with Head 146 not out and Steve Smith 95 not out.

Smith brought up the pair's 250 stand off the last ball of the day when he guided Mohammed Shami through the covers for a sweetly timed four.

The fourth-wicket duo had come together with Australia in trouble at 76-3 after being sent into bat in bowler-friendly conditions.

But as the sun burst through the clouds in south London, the runs started to flow.

"Losing the toss this morning, we've done exceptionally well," Head told Sky Sports.

"I was trying to make sure I was in really good positions today. I got tested through parts of that.

"I just tried to work through those periods and be adjustable and stay relaxed."

Head was troubled by left-arm spinner Ravindra Jadeja but by counter-attacking from the start of his innings -- 24 of his first 27 runs came in boundaries -- he put the pressure back on the bowlers.

With Smith, who before this match averaged nearly 98 in Tests at The Oval, batting in more conventional fashion it gave the 29-year-old Head freedom to keep playing his shots.

"I always love batting with Steve (Smith)," said Head. "You need to have plans bowling to him because he's so unique.

"You say he played second fiddle but I always feel I'm playing second fiddle to him and can go a bit under the radar."

By the time India tested Head with the short ball, he was well set and a pulled single off Shami took him to a sixth Test hundred in just 106 balls, including 14 fours and a six.

"Travis just goes about his business, sees the ball and hits it," said Smith, whose fifty came off 144 balls.

"He shifted the momentum. It was a tremendous innings."

India took the new ball before the close but it made little difference on a day when captain Rohit Sharma would have been looking for many more wickets after winning the toss.

And as Smith and Head repelled India, he might also have wondered about the wisdom of leaving out off-spinner Ravichandran Ashwin, the world's top-ranked Test bowler, who could have been a threat against an Australia top five featuring three left-handers.

India had started strongly in what was their second WTC final after losing to New Zealand in the inaugural 2021 showpiece in Southampton.

Mohammed Siraj removed Usman Khawaja for a duck with an excellent wobble-seam delivery and Australia were 2-1, to the raucous delight of an overwhelmingly pro-India crowd of nearly 23,000.

But David Warner, who had managed just one century in his previous 32 Test innings, dug in before the increasingly assured opener struck Umesh Yadav for three fours in successive deliveries.

The 36-year-old left-hander's promising innings ended on 43 when a gloved pull off medium-pacer Shardul Thakur was well caught down the legside by diving wicketkeeper Srikar Bharat.

Marnus Labuschagne, the world's top-ranked Test batsman, fell early in the second session for his lunch score of 26 when he was bowled between bat and pad by a Shami inswinger.

The WTC is the only major men's cricket trophy Australia have yet to win.

The fixture also marks the start of a packed schedule of six Tests in eight weeks for Australia, including a five-match Ashes series against England.

(AFP)