Replying to the 40-time champions' mammoth first innings total of 610 for 9 declared, UP were at a healthy 155 for one before losing four wickets to be 350 for five at close, still trailing the home team by 260 runs at the Wankhede Stadium.
At stumps, leg spinner Piyush Chawla (54 in 55 balls) and wicketkeeper Ekalavya Dwivedi (50 in 88 balls) were leading the fight for the first innings lead.
The big break for the hosts was given by their partnership breaker Abhishek Nayar, who accounted for both Asnora and Sarfaraz soon after tea, taken when UP were 241 for 3.
Asnora, who batted from yesterday evening, hit 13 fours in his 262-ball knock before getting bowled, while Sarfaraz fell a victim to his impetuosity and was trapped leg before after striking two sixes and four fours. Captain Suresh Raina flopped, making only 9.
The hosts' leading new ball bowlers, Shardul Thakur and Dhawal Kulkarni, were yet to take a wicket on the slow track.
Brief scores:
Mumbai 610/9 declared
Uttar Pradesh 350/5 (Tanmay Srivastava 37, Himanshu Asnora 92, Umang Sharma 53, Sarfaraz Khan 44, Piyush Chawla 54 not out, Eklavya Dwivedi 50 not out; A Nayar 2/37).
