The experienced left-hander had a lucky break in the morning session when he pulled left-arm paceman Ashish Nehra straight to Akash Chopra only for West Indian umpire Steve Bucknor to signal a no-ball for over-stepping.

Television replays showed the decision was desperately close to a legal delivery.

"This is the funniest thing about Test cricket... if he'd have caught that and it had been a no-ball (that hadn't been called) I'd be the unluckiest bloke in the world and now that he catches it I'm the luckiest bloke in the world it's a very fine line," Langer said after play.

Langer rated the hundred among the best of his 16 in Tests because the conditions had been so tough as the ball seamed and bounced on a grassy pitch.

"It's right up there among my best, if not the best, because of how hard I had to work. That's as hard as I've worked for a very long time," Langer said.

"We always aim to win the first session and from there we try to win the first day of the Test series.

"They had very good conditions to bowl at us and we only lost a couple of wickets. It's been a huge day for us."

Langer predicted the tourists would struggle to recover after failing to make the most of favourable conditions.

India won the toss and sent the Australians in on a green wicket that was difficult to bat on, but the hosts survived the initial onslaught to lay the foundations for a massive total.

Langer said Australia captain Steve Waugh told his players he planned to bat first if he won the toss, even though the pitch looked menacing.

"We've learnt our lessons at the Gabba. If you can get through those first 20 overs or so when it's really tough then you can really set up the game," Langer said.

"It was very hard out there, as hard as I've ever seen it, but it started to play okay as long as you watched the ball carefully.

"The Indian bowlers must have thought it was heaven bowling on that wicket. The ball was flying around everywhere and it was scary just watching it from the non-striker's end."

Langer said the key to Australia's strong batting display was to play with confidence even when the bowlers were threatening to dismiss them.

"It takes courage to be aggressive but we know it works. We always back ourselves in that situation. We don't hesitate," Langer said.

"We didn't go out there just to score quickly. There were times when it was really hard to score but I guess we're really good at punishing loose balls."