Karnataka were eventually bowled out for 321.
Uttar Pradesh made 281 in their first essay. Karnataka resumed the third day on their overnight score of 168/4, with Abhishek Reddy (32 off 102 balls) and Shreyas Gopal (58 off 182 balls) at the crease.
While Reddy fell early, Gopal held one end and hit six boundaries in his knock. Reddy and Gopal conjured a 38-run stand for the fifth wicket before Reddy was caught by Rinku Singh off slow left-arm bowler Saurabh Kumar (6-116).
Then Uttar Pradesh dismissed rival wicket-keeper BR Sharath (16) and David Mathais (4) in quick succession to peg back the visitors.
However, then Suchith joined hands with Gopal, and the two not only frustrated the UP bowlers, but also took the team on the cusp of getting the first inning lead.
Suchith hit two boundaries. When Gopal fell, Karnataka were 279-8, just two runs behind Uttar Pradesh’s first innings total.
Later, Mithun, who had bagged six wickets, also made a fine unbeaten 34.
In their second essay, Uttar Pradesh was teetering at 29/1, having lost their opener Aryan Juyal (0). Juyal had made a hundred in the first innings. The visitors trail Karnataka by 11 runs and will need to bat throughout the fourth and final day to avoid defeat.
Ricky Bhui cracked an unbeaten 144 while pacer Cheepurapalli Stephen scalped four wickets as Andhra Pradesh took complete control of their Group A Ranji Trophy match against Delhi on the third day Ongole on Thursday.
After conceding a 153-run first innings lead to Andhra, Delhi were reduced to 89 for 6 in 28 overs in their second innings with Stephen running through their top-order.
As Delhi still trail by 64 runs with just four second innings wickets in hand and one day left in the match, Andhra can aim for a bonus point and grab seven points if they can notch up an innings win on Friday.
Resuming at overnight individual score of 70 and team total of 249 for 6, Bhui batted for 40 overs with the tailenders and carried his bat through the innings to take Andhra to 368 all out from 127 overs.
Bhui faced 313 balls during his unbeaten knock and struck 15 boundaries and four sixes.
Delhi pacer Navdeep Saini, who was drafted in for injured Deepak Chahar in the Indian squad for the West Indies ODI series, took a five-for but his side had little to cheer apart from that.
In the second innings, Delhi were in a precarious position with Lalit Yadav holding fort on 23 not out from 48 deliveries, along with Vikas Mishra (7 not out), at stumps on the third and penultimate day.
Openers Kunal Chandela and Hiten Dalal contributed just 19 and 13 runs respectively while four Delhi batsmen could not reach double-digit figures.
Stephen’s victims were Chandela, Dalal, one-down Kunwar Bidhuri (2) and Jonty Sidhu (9) while pace colleague KV Sasikanth got the wickets of captain Nitish Rana (8) and wicketkeeper Anuj Rawat (0).