Gill says '70-30' for India victory as England chase 399
England, who lead the five-match series 1-0, reached 67-1 at stumps after opener Ben Duckett fell for 28 in Visakhapatnam.
Left-hander Duckett put on an attacking 50-run stand with fellow opener Zak Crawley, who is still batting on 29, before Ravichandran Ashwin got him out for his 497th Test wicket.
Nightwatchman Rehan Ahmed, on nine, joined Crawley with England needing another 332 for victory.
"Definitely pleased but I left a few out there. We could have done with a few more runs," said Gill.
"I think it's 70-30 at the moment. Morning session will be key. We've seen there is moisture in the morning, and help for fast bowlers and spinners."
The highest fourth-innings target successfully chased against India is England's 378 at Edgbaston in 2022, and the most successful in India was when the hosts got 387 against England in 2008.
Spinners Tom Hartley and Ahmed combined to bowl out India for 255 after Gill's 104 on a day of bowling and fielding brilliance.
Veteran pace bowler James Anderson struck early to remove the openers, and India slipped further after a stunning catch by captain Ben Stokes before Gill stabilised the innings.
Anderson backed England to do the job with their attacking "Bazball" style of play, which was on display when they turned a 190-run deficit in the opener to go one up.
"The chat last night from the coach was that if they get 600, we were going to go for it," said Anderson.
"It makes it very clear to everyone that we will try to do it tomorrow. I know there are 180 overs left in the game, but we will try to do it in 60 or 70."
Gill hits from
Gill hit his third Test ton, and first in his 12 innings since March 2023, to pull India out from 122-4 with two key stands including 89 runs with Axar Patel.
He reached the hundred with a single off debutant spinner Shoaib Bashir and raised his bat to a cheering Sunday crowd.
He soon attempted a reverse sweep and departed when Bashir got him caught behind, a dismissal that was turned down by the umpire but replays showed the ball grazed the batsman's glove before wicketkeeper Ben Foakes took a sharp catch.
Gill had two lucky escapes on four, both close lbw calls and one successfully reviewed, but then batted fluently with his flicks and drives until his exit.
England kept chipping away as Hartley, who returned figures of 4-77 with his left-arm spin, sent back Axar lbw for 45 to leave India six down by tea.
Ashwin played a stubborn knock of 29 before Ahmed took him down to wrap up the innings with his third strike.
England missed part-time spinner Joe Root on the field for most of the day after the senior batsman hurt his finger while fielding in the morning, but Anderson said the time away was precautionary.
In the first session, Shreyas Iyer made 29 and was out after a moment of magic by Stokes.
Iyer attempted a big hit off Hartley but Stokes sprinted back from mid-off and dived at full stretch to pull off a screamer of a catch.
Anderson, in an excellent morning spell of fast bowling, rattled Rohit Sharma's stumps with a superb delivery that pitched and moved away from the right-hander.
The old warhorse then got the left-handed Yashasvi Jaiswal caught at first slip, for his 695th Test wicket.
India had a lead of 143 at the start of their second innings and began the day on 28-0.