Gautam did the star turn for Rajasthan after its rival had posted 268 for 8 riding on Siddhesh Lad's second century in the tournament.
The Rajasthan's opener knock was embellished with 16 boundaries and four sixes.
For Mumbai, Lad, who stroked an exact 100 (8x4, 4x6) and Prithvi Shaw 52 (7x4), were the main scorers.
In another match, a blistering 158 off 111 balls by Rajat Patidar powered Madhya Pradesh to a comprehensive eight-wicket win over defending champion Tamil Nadu.
The home side's third straight loss effectively ended their hopes in the tournament.
Faced with a rather daunting target of 303, Madhya Pradesh went on the attack from the start as openers Patidar and Naman Ojha unleashed an array of shots.
Patidar and Ojha added 65 runs before the latter fell to Aswin Crist for 39 (5X4, 1X6).
This brought together Patidar and Rameez Khan, who took the game away from the host with a massive 209-run partnership in 243 balls.
Patidar was in control right through his knock and hit 20 fours and four sixes as he peppered the Pachaiyappa's College ground with shots all round the wicket.
India Test star Ravichandran Ashwin, who has bowled with control throughout the tournament and tried his hand at leg-spin too, could not do anything to break the partnership or stem the flow of runs.
He finished with figures of none for 64 in 10 overs.
Earlier, Tamil Nadu recovered after losing Ganga Sridhar Raju (0) in the third over and Kaushik Gandhi (7) in the seventh over with wicketkeeper-batsman N Jagadeesan (99) stringing together a 107-run stand in 120 balls with B Aparajith (43).
Jagadeesan was unlucky to miss his ton as he fell caught behind (by Ojha) to Puneet Dubey.
Vijay Shankar was his usual aggressive self and ran hard between the wickets and compiled a stylish 84 (62 balls, 7 fours, two sixes) but his exit triggered a collapse.
The team slid from 284 for 5 to end at 302 for 8 with the last five overs yielding just 20 runs.
Brief scores: Tamil Nadu 302 for 9 in 50 overs (N Jagadeesan 99 (108b, 11x4, 1x6), B Aparajith 43, Vijay Shankar 84 (62b, 7x4, 2x6), B Anirudh Sitaram 39, Ankit Singh Kushwah 3 for 59) lost to Madhya Pradesh 303 for 2 in 46 overs (Naman Ojha 39, Rajat Patidar 158 (111b, 20x4, 4x6s), Rameez Khan 78 not out (115b, 8x4).
Points: Madhya Pradesh: 4 (8); Tamil Nadu: 0 (4).
Goa 188 in 47.4 overs (Sugan Kamat 28, Snehal Kauthankar 43, Suyash Prabhudessai 38, P Girinath Reddy 4 for 32) lost to Andhra 191 for 9 in 49.3 overs (K S Bharat 30, Ricky Bhui 56 not out (86b, 6x4, 1x6), Lakshay Garg 3 for 32, Vijesh Prabhudesai 3 for 43).
Points: Andhra: 4 (12); Goa: 0 (8).
Mumbai 268 for 8 in 50 overs (Prithvi Shaw 52 (54b, 7x4), Siddhesh Lad 100 (105b, 8x4, 4x6s), Syed Khaleel Ahmed 4 for 35)lost to Team Rajasthan 272 for four in 47.3 overs (Amit Gautam 149 not out (136b, 16x4, 4x6s), Mahipal Lomror 81 (77b, 7x4, 2x6), Shivam Dube (two for 36).
Points: Team Rajasthan: 4 (4); Mumbai: 0 (12).
(This story has not been edited by Business Standard staff and is auto-generated from a syndicated feed.)