Justin Langer is one of those rare sporting characters who is most intimidating when he smiles.

The Australian coach wore a typically disconcerting grin on Sunday morning, shortly before play began at the Gabba. He was talking about Mitchell Starc. Langer seemed certain it would be a big day for the left-arm paceman.

In the early stages of the first session, the prophecy was playing out. Starc’s pace was up, Cheteshwar Pujara and Ajinkya Rahane were a little jumpy, and the edges were coming thick and fast.

All was primed for one of those performances Starc has produced so often in home Tests — four or five quick wickets and a couple of bruises to bully out the middle and lower-order batsmen.

Langer’s faith in the New South Welshman is well-founded in statistics. In the last three Australian summers, Starc’s returns have been 29 wickets at 17.44 apiece, 25 at 25.84 and 22 at 23.54. Those are fine numbers for the third option in a world-beating pace attack. Starc’s remarkable strike rate of 48.9 is the best of any bowler in Australia’s all-time top 20.

Yet he has flagged noticeably this summer, an underacknowledged factor in Australia’s struggles.

Leading into this game, nine series wickets at 31.66 probably flattered his performances. Along with Nathan Lyon (six wickets at 57.66 in the first three Tests), he’s been fortunate that the startling brilliance of Pat Cummins and Josh Hazlewood and the uncertainty of Australia’s batting line-up have provided ample distraction.

Both Starc and Lyon could and probably should have turned a corner today, padding their stats and reconfirming their positions. Starc looked most likely. He was also a little unlucky; he certainly didn’t benefit from Tim Paine’s reactive placement of floating slips, nor the rub of the green.

After lunch, Hazlewood snuffed out promising innings from Mayank Agarwal and Rishabh Pant. The score was 6-186, unheralded newbies Washington Sundar and Shardul Thakur were at the crease and another Brisbane rout looked certain. It was, in other words, a situation tailor-made for Starc and Lyon.

Instead, India surged again. An audacious, record-breaking seventh-wicket partnership of 125 took hold and the Border-Gavaskar Trophy started slipping away before Australia’s eyes.

In his milestone Test, Lyon was milked for runs like a novice, not a man on the cusp of 400 Test wickets. Just before the final drinks break, Washington dropped to one knee for a slog-sweep and launched the spinner over the ropes with a no-look six.

After a defensive prod back down the pitch, Lyon was reduced to pegging the ball back at the debutant’s head.

If that wasn’t bad enough, Shardul’s sparkling knock went close to demoralising Australia. A 29-year-old fill-in with a first-class batting average of 16, he smacked Starc around like he was a village trundler.

And the highlights were entirely orthodox, not lucky swipes: after tea, Shardul pushed confidently onto the front foot and stroked a delightful straight drive to the fence when Starc over-pitched. Two deliveries later, the retaliatory short ball was dispatched over point for four more.

A week ago, Paine crowed that he couldn’t wait to get the Indians onto the Gabba. On Sunday, he was spilling catches, wasting reviews and tactical inspiration was in short supply.

With Cummins misfiring for the first time all summer, Starc was doubly exposed. A freeze-frame graphic spoke of his scattergun method: at the point of delivery, all the other Australian bowlers had their eyes fixed on the batsman. Starc’s were firmly shut.

Incensed at the impertinence of India’s newest pair of heroes, Starc cranked the speed dial up to 150kph and aimed at the body — his go-to move this summer, but not a very successful one.

Even at that speed, you significantly reduce your chances of taking wickets if barely one in 10 deliveries is aimed at the stumps. Surprise surprise, when Shardul was finally dismissed for 67, it was because Cummins returned and bowled stump-to-stump.

Does Australia deserve to win this series? It is hard to mount a convincing argument that a pair of brilliant batsmen and two great fast bowlers make a champion team.

India, on the other hand, has showed that it can throw together almost any combination of 11 fit players and thrive, even at bogey grounds, even at the end of a punishing tour, even when exhaustion is surely setting in.

There was something else Langer said before play that stuck in the mind as India’s innings wore on. For advice on the Brisbane thunderstorms that might wipe out a chunk of day five and ensure India’s retention of the trophy, the coach has been leaning on Michael Neser, the wily local paceman whose primary tasks this summer have been to work on his luscious beard and bowl in the nets.

On today’s evidence, he can consider himself unlucky that his only other role is amateur meteorologist.

Justin Langer is one of those rare sporting characters who is most intimidating when he smiles.

The Australian coach wore a typically disconcerting grin on Sunday morning, shortly before play began at the Gabba. He was talking about Mitchell Starc. Langer seemed certain it would be a big day for the left-arm paceman.

In the early stages of the first session, the prophecy was playing out. Starc’s pace was up, Cheteshwar Pujara and Ajinkya Rahane were a little jumpy, and the edges were coming thick and fast.

All was primed for one of those performances Starc has produced so often in home Tests — four or five quick wickets and a couple of bruises to bully out the middle and lower-order batsmen.

Langer’s faith in the New South Welshman is well-founded in statistics. In the last three Australian summers, Starc’s returns have been 29 wickets at 17.44 apiece, 25 at 25.84 and 22 at 23.54. Those are fine numbers for the third option in a world-beating pace attack. Starc’s remarkable strike rate of 48.9 is the best of any bowler in Australia’s all-time top 20.

Yet he has flagged noticeably this summer, an underacknowledged factor in Australia’s struggles.

Leading into this game, nine series wickets at 31.66 probably flattered his performances. Along with Nathan Lyon (six wickets at 57.66 in the first three Tests), he’s been fortunate that the startling brilliance of Pat Cummins and Josh Hazlewood and the uncertainty of Australia’s batting line-up have provided ample distraction.

Both Starc and Lyon could and probably should have turned a corner today, padding their stats and reconfirming their positions. Starc looked most likely. He was also a little unlucky; he certainly didn’t benefit from Tim Paine’s reactive placement of floating slips, nor the rub of the green.

After lunch, Hazlewood snuffed out promising innings from Mayank Agarwal and Rishabh Pant. The score was 6-186, unheralded newbies Washington Sundar and Shardul Thakur were at the crease and another Brisbane rout looked certain. It was, in other words, a situation tailor-made for Starc and Lyon.

Instead, India surged again. An audacious, record-breaking seventh-wicket partnership of 125 took hold and the Border-Gavaskar Trophy started slipping away before Australia’s eyes.

In his milestone Test, Lyon was milked for runs like a novice, not a man on the cusp of 400 Test wickets. Just before the final drinks break, Washington dropped to one knee for a slog-sweep and launched the spinner over the ropes with a no-look six.

After a defensive prod back down the pitch, Lyon was reduced to pegging the ball back at the debutant’s head.

If that wasn’t bad enough, Shardul’s sparkling knock went close to demoralising Australia. A 29-year-old fill-in with a first-class batting average of 16, he smacked Starc around like he was a village trundler.

And the highlights were entirely orthodox, not lucky swipes: after tea, Shardul pushed confidently onto the front foot and stroked a delightful straight drive to the fence when Starc over-pitched. Two deliveries later, the retaliatory short ball was dispatched over point for four more.

A week ago, Paine crowed that he couldn’t wait to get the Indians onto the Gabba. On Sunday, he was spilling catches, wasting reviews and tactical inspiration was in short supply.

With Cummins misfiring for the first time all summer, Starc was doubly exposed. A freeze-frame graphic spoke of his scattergun method: at the point of delivery, all the other Australian bowlers had their eyes fixed on the batsman. Starc’s were firmly shut.

Incensed at the impertinence of India’s newest pair of heroes, Starc cranked the speed dial up to 150kph and aimed at the body — his go-to move this summer, but not a very successful one.

Even at that speed, you significantly reduce your chances of taking wickets if barely one in 10 deliveries is aimed at the stumps. Surprise surprise, when Shardul was finally dismissed for 67, it was because Cummins returned and bowled stump-to-stump.

Does Australia deserve to win this series? It is hard to mount a convincing argument that a pair of brilliant batsmen and two great fast bowlers make a champion team.

India, on the other hand, has showed that it can throw together almost any combination of 11 fit players and thrive, even at bogey grounds, even at the end of a punishing tour, even when exhaustion is surely setting in.

There was something else Langer said before play that stuck in the mind as India’s innings wore on. For advice on the Brisbane thunderstorms that might wipe out a chunk of day five and ensure India’s retention of the trophy, the coach has been leaning on Michael Neser, the wily local paceman whose primary tasks this summer have been to work on his luscious beard and bowl in the nets.

On today’s evidence, he can consider himself unlucky that his only other role is amateur meteorologist.