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 today.

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.