The victory at the Wankhede Stadium was the third in a row for East who now just have to beat West in their last round robin game on February 18 morning to sew up the title.
The 19-year-old Virat slammed a superb, unbeaten 74 in 48 balls and put on 149 runs in just 87 balls with Tiwary, who cracked 75 not out in 43 balls, to guide East to 162 for 2 in 16.3 overs, chasing North's 159 for 9.
If East lose the game against the hosts and if Central Zone, their lone rival for the crown at the end of the penultimate day of the competition, beat South Zone on Saturday afternoon, there will be a tie on points (12 each) and the net run-rate will come into the picture to decide the winners.
After their third win today, East were sitting pretty on 12 points with a net run-rate of plus 1.185, while Central, who have 8 points to their credit after two wins and a loss, are second with a net run-rate of minus 0.064.
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In the first match of the day South Zone, powered by opener Mayank Agarwal's 70 off 36 balls, notched their first win of the tournament by defeating West Zone by five wickets.
Riding on Agarwal's breezy knock, South overhauled West's total of 140 for 9 by making 141 for 5 in 17.4 overs.
In the East-North afternoon contest, the latter, without Rishabh Pant, who has also been released to play for India A, were restricted to less than 160 which was not par for the course even on the worn-out track.
Having lost openers Shikhar Dhawan, Gautam Gambhir and Unmukht Chand, playing his first game in place of Pant, with 85 on board in the 12th over, North needed Yuvraj to play a bigger knock but it was not to be.
The rest of the batting caved in against left-arm spinner Pragyan Ojha, who grabbed three wickets.