Uttar Pradesh were fighting with their backs to the wall in quest of the first innings lead after Mumbai ran up a mammoth, season-high score of 610 for nine declared on day two of the four-day Ranji Trophy Group B game.
In reply, UP plodded their way to 51 for no loss in 27 overs, trailing the home team by 559 runs, with left-handed openers Tanmay Srivastava (30) and Himanshu Asnora (21) the unbeaten men at stumps at the Wankhede Stadium after batting for the entire final session of play.
In the morning, Mumbai commenced at their commanding overnight score of 407 for 4 and with Rohit Sharma at the crease on an impressive 110, there were hopes of some sparkling stroke-play.
However, it went up in smoke in the second over when Sharma, who would join the Indian second Test squad at Bengaluru after the end of this game, flashed outside the off stump against tall UP medium pacer Ankit Rajput and perished for 113 after a stay of 206 minutes.
The UP bowlers then kept things tight though they could not produce something extra to defeat the new pair of overnight unbeaten Siddhesh Lad and Abhishek Nayar.
The runs came at a trickle as the two batsmen added 90 runs in two and a half hours before left-handed Nayar departed for an unconvincing 42 off 113 balls, in the second over after lunch.
Lad, at the other end, was slightly more enterprising and hit ten fours and a six in his 176-ball essay that consumed 281 minutes, but generally the home team batting lacked aggression.
The arrival of Shardul Thakur at the crease at the fall of Dhawal Kulkarni saw the scoring rate perk up as the medium pacer made a brisk 56 off 61 balls, striking six fours and a six.
Lad finally fell to leg spinner Piyush Chawla while Thakur holed out in the deep in the first over from part time bowler Umang Sharma who was brought on to bowl after the score crossed the 600 mark.
Mumbai declared the innings closed at 610 for 9 and tea was called, after adding 203 runs in 65 overs and 291 minutes from morning.
In a generally unimpressive bowling display, Bhuvneshwar Kumar - who will also leave for Bengaluru after the game to join the rest of his second Test team-mates took 2 for 99 while Rajput secured 2 for 112.
Brief scores:
Mumbai 610 for 9 decl. (S Iyer 137, R Sharma 113, S Lad 89; B Kumar 2 for 99, A Rajput 2 for 112)
UP 51 for no loss (T Srivastava not out 30, H Asnora not out 21).