England captain Joe Root has urged his team to produce a "ruthless" display in the fourth Test against India at the Oval starting Thursday.
England's innings and 76-run victory at Headingley last week has left the five-match series all square at 1-1.
But with wicketkeeper-batsman Jos Buttler absent to attend the birth of his second child and concerns about the impact a gruelling schedule of three Tests in three weeks will have on their fast bowlers, England could still make as many as three changes to a winning side.
"Now is when the hard work starts," England captain Root told reporters on Tuesday.
"We've got to look to go even further, dig deeper and really start to go through the gears," added Root, who scored his third hundred in as many Tests last week -- his sixth of 2021 -- and is now set to climb to the top of the International Cricket Council Test batting rankings when the points system is updated on Wednesday.
"A world-class side like India, led by Virat Kohli, I expect nothing less than a response. It would be naive to think otherwise. We've just got ourselves back to level and, if we find ourselves ahead of the game at any stage, we must get ruthless again."
Jonny Bairstow will replace Buttler behind the stumps, with either Dan Lawrence or Ollie Pope filling the vacancy in the middle order.
The more awkward issue for England is whether they should rest either or both James Anderson and Ollie Robinson after the new-ball duo starred at Headingley.
England coach Chris Silverwood has spoken of not wanting to "break" his quicks, but the inflexible application of a rotation policy contributed to the team's series loss in India earlier this year.
Both Anderson and Robinson, however, have bowled more than 116 overs each in the first three games of the series, with Robinson -- whose Headingley match haul of 7-81 was his best in Tests -- increasingly influential in an attack missing Stuart Broad, Jofra Archer, Olly Stone and Ben Stokes.
"Trying to manage workloads alongside performance is something in the current climate, with the games coming thick, that is always going to be tricky," said Root.
"You come off a win like last week and there's continuity of confidence and trying to replicate a similar performance, but you're trying to balance that and make sure you don't blow someone out and injure someone."
Alternative bowling options for England could include fast bowler Mark Wood, trying to overcome a shoulder injury and the recalled Chris Woakes, who could yet pay his first Test in a year if England drop fellow all-rounder Sam Curran.
Faced with an Oval pitch known to take turn, India must decide if they can continue to omit off-spinner Ravichandran Ashwin.
Ashwin has 413 Test wickets and five hundreds to his credit, but is yet to feature in this series, with left-arm spinner Ravindra Jadeja supporting a four-man pace attack.
"I think his record speaks for itself, he's a world-class player," said Root of Ashwin, who had a brief spell with Oval-based Surrey earlier this season.
"We've seen him score runs and take wickets against us and we know what he is capable of in the Test arena. Ultimately you can get wrapped up in playing the player but it's important that you just play the delivery, play the situation you find yourself in."
A see-saw series -- a rain-affected draw in Nottingham was followed by India's 151 run-win at Lord's before they collapsed to 78 all out at Leeds -- has left Kohli adamant his side will not be "demoralised" by last week's loss.
"If what happens in one game guarantees you the same thing in the next game, we should have smashed England again," the India captain added.
India were dismissed for just 36 while losing the first Test against Australia in Adelaide in December only for an injury-hit squad to claim a memorable 2-1 series win.
"We like to be in this situation where people start coming at us with doubts and really start questioning the ability of our team," said Kohli. "That is the situation we love best."