Overnight batsmen Ajay Kudua's 123 and Sunil Oasis's unbeaten 63 prolonged Delhi's agony even though the hosts did well to restrict Kerala by dismissing the tailenders cheaply at the Harbaksh stadium.
In reply, Gautam Gambhir made unbeaten 61 and Rajat Bhatia 39 not out in Delhi's score of 108 for no loss at stumps on the penultimate day of the four day match.
Earlier, over 150 minutes of play was lost due to fog and dew on the pitch and the day's proceedings started well after the lunch time.
Kudua and Oasis added 127 runs for the sixth wicket before Sarandeep struck removing the former, who offered a catch to Vijay Dahiya. Kudua's 263-ball knock contained 14 boundaries.
Then it was not a difficult job for the hosts as they dislodged the visitor's late-order with regular strikes from Sarandeep and left-arm spinner Rahul Sanghvi, both of whom returned with identical figures of four for 83.
As a draw looks imminent, after Kerala batted too slowly for their 371 and a substantial time on the first three days was lost due to rain, fog and bad light, Delhi can at the most add two more points from the game to their tally of six, that too if they manage a first innings lead.
Meanwhile, in Mumbai, fine bowling by off-spinner Ramesh Powar (four for 69) and medium pacers Usman Malvi (two for 28) and Swapnil Hazare (two for 28) helped the hosts to bowl out former champions Railways for a paltry 198 off 97.5 overs in their first innings.
However, despite bowling out the opposition for a small score, the Ranji champions Mumbai failed to enforce the follow-on and were sitting pretty at 82 for three off 42 overs in the their second innings, an overall lead of 272 runs, when the stumps were drawn.
Railways, resuming at their overnight score of 103 for three, crawled to 117 off 58.3 overs before losing Shreyas Khanolkar for 41 off 107 balls with five fours after he had added 79 runs with his skipper Sanjay Bangar (49 off 209 balls including four fours and a six) for the fourth wicket off 35.2 overs in 147 minutes.
Bangar did not stay for long after Khanolkar was bowled by Hazare. Bangar was caught by wicketkeeper Vinayak Samant off Malvi. Railways lost three more quick wickets that of Sudhir Wankhede (2), Harvinder Singh (0) and Raja Ali (5) to be 156 for eight off 83.3 overs.
However, aided by Siddharth Verma's unbeaten 44 off 129 balls with four fours and a six, and his 37-run ninth wicket partnership with tailender Zakir Hussain (15 off 44 balls), Railways managed to reach 198 allout 38 minutes after lunch.
Mumbai lost three quick wickets with just 28 runs on the board before southpaw Vinod Kambli (batting on 28 off 80 balls and Amol Muzumdar (batting 19) steadied the second innings with an unbroken 54 runs third wicket partnership.
Kerala continues to frustrate Delhi
Powar's century puts Mumbai on top