The home team's gigantic 649 still seems a long haul as Delhi would need another 373 runs on the final day to ensure three points.
With only six wickets in hand, this looks improbable at the moment with Gambhir only having vice-captain Milind Kumar (10 batting) for company.
The likes of Unmukt Chand (16) and Rishabh Pant (41) did not show the wherewithal to stay at the crease and support the team's oldest cricketer, who mostly waged a lonely battle with partial support from Dhruv Shorey (64).
After Milind, the next batsmen to come in will be all-rounder Manan Sharma, who has had a nightmarish game with the ball.
For Delhi, the target will be not to get all out and prevent Karnataka from at least getting three points from the game.
With the pitch showing no signs of wear and tear, it will be difficult for Karnataka to push for innings victory even if they can fold Delhi's first innings by the first session.
The day was all about Gambhir showing how to make runs at the first-class level. He has so far faced 237 balls and hit 20 boundaries.
There were straight drives and a few cover drives off seamers R Vinay Kumar (0/60 in 16 overs) and Abhimanyu Mithun (1/56 in 17 overs).
Against spinners Shreyash Gopal (0/64 in 16 overs) and Krishnappa Gowtham (1/46 in 20 overs), he was cautious and waited for the loose deliveries.
However that was not the case with former U-19 World Cup winning captain Chand, whose prolonged failure has raised questions about his place in the team.
On the day, he did all the hardwork, staying at the wicket for the first hour before edging one off military medium pacer Stuart Binny to keeper CM Gautham behind the stumps.
Shorey, who had a good outing against Uttar Pradesh, then forged a good 110-run stand with Gambhir, hitting eight boundaries off 97 balls. Once he was cleaned up by Mithun, skipper Pant came to the crease.
He got into the act hitting three boundaries and two sixes off 59 balls adding 83 runs in 22.4 overs.
However when the situation demanded responsible batting, Pant tried to play a delicate late cut off Gowtham, only dragging the ball back to his stumps to put Delhi in further trouble.
Karnataka 1st Innings 649. Delhi 1st Innings 277/4 (Gautam Gambhir 135 batting, Dhruv Shorey 64, Rishabh Pant 41)
Mahasrashtra 1st Innings 481. Railways 1st Innings 330/5 (Pratham Singh 73, Nitin Bhille 56, Shivakant Shukla 62, Chirag Khurana 2/50)
Uttar Pradesh 349 and 221/2 (Umang Sharma 131 batting). Assam 318 (Shib Sankar Roy 72, Rishav Das 52, Saurabh Kumar 5/54).
First Published: November 12, 2017, 7:45 AM IST