Virat Kohli hit his first Test century in over three years with a towering 186 on Sunday to give India a sniff of what would be a stunning victory in the fourth Test against Australia.

The hosts finished their first innings on 571 to overhaul Australia's 480 and get a first-innings lead of 91 on another run-filled day four at the world's biggest cricket stadium in Ahmedabad.

Kohli was the last man out after he fell to Todd Murphy in the final session of play as India lost their ninth wicket and Shreyas Iyer did not bat due to back pain.

His wife, Bollywood actor Anushka Sharma, took to social media after the end of day's play to say the former captain was "playing through sickness" during his epic knock.

Australia reached three for no loss at stumps with Travis Head getting the runs while alongside nightwatchman Matthew Kuhnemann.

The left-handed Kuhnemann made a surprise entry to the crease after opener Usman Khawaja, who hit 180 in Australia's innings, did not come out to bat after getting hurt on the field.

Axar Patel, who shared a 162-run sixth-wicket partnership with Kohli, admitted that another Australia collapse like in the earlier Tests was unlikely, but that India would still try.

"It will not be like we will run through them like in the previous three games. We will have to work hard, keep patience and bowl on good areas," Axar said.

Kohli ruled the day with his 28th Test ton after he got a single off spinner Nathan Lyon in the second session to bring the house down as fans went wild with celebration.

Kohli, who now has 75 international tons across three international formats, kissed his locket before looking up to the sky.

- Smash and grind -

Resuming on 59 after reaching his first Test half-century on Saturday since January 2022, the landmark came after a patient innings of 241 balls.

"He's a class player and he didn't give us a chance really," Australia wicketkeeper Alex Carey said of the star batsman.

"We knew it was going to be tough bowling to Virat. We were able to contain him as much as we could and try to take wickets around him."

Kohli then hit a flurry of fours after reaching his hundred and along with an attacking Axar, who made 79.

Khawaja attempted to catch an Axar six at the boundary but could not stay inside the rope, hurting his foot in the process and limping off the field.

It was termed as "lower leg soreness" by a team spokesperson and it was unclear if the batsman would play on the fifth day.

Kohli got past 150 after tea and Axar reached his third half-century of the series to wear down the opposition bowlers on a pitch vastly different from the rank turners in the previous three matches.

Spinners Lyon and Murphy bowled 110.5 overs between to get three wickets each on another day of hard grind for the bowlers.

Axar went into fifth gear after his fifty as he slogged and smashed Kuhnemann for two sixes in an over before being bowled off an inside edge by Mitchell Starc.

Kohli lost his overnight partner Ravindra Jadeja for 28 in the morning session and Srikar Bharat fell in the afternoon after the wicketkeeper-batsman hit 44 in an 84-run partnership with the former captain.

Opener Shubman Gill led India's strong reply on Saturday with his 128.

India need a win to clinch the series and be sure of a berth in the World Test Championship final in June. World number one Australia have already booked their place.