Vyas put on a 282-run opening stand with Harvik Desai, who made 100 off 107 balls, as Saurashtra posted 397 for 4. In reply, Manipur were bowled out for 115. This was Saurashtra's second straight win in the competition.
On Saturday, they opened their campaign with a seven-wicket win over Chandigarh, with Vyas contributing a 64-ball 61 in a chase of 216.
Vyas has been in excellent form lately. He topped the run charts for Saurashtra at the Syed Mushtaq Ali Trophy T20s earlier in the month, where they made the semi-finals. Vyas smashed 314 runs in seven innings at a strike rate of 177.40 and a best of 97 not out against Nagaland. He made one other 97, against Baroda. Overall, he was the fifth-highest run-getter in the tournament, finishing just 49 runs behind Yash Dhull, who topped the charts.
Vyas made his List A debut in 2015 but has only recently become a regular member of the team. He started as a middle-order batter but has moved up the order of late, with the team management pushing him up to bat in the top three.
Records-wise, Ajinkya Rahane's 187 for Mumbai against Maharashtra in 2007-08 was the highest individual List A score in the tournament for nearly a decade until Uttarakhand's Kaushal scaled the 200 barrier in the 2018-19 season against Sikkim.
Since then, the tournament has seen four other double-centuries, including the one by Vyas on Sunday. Shaw's 227 not out for Mumbai against Puducherry in the previous season remains the highest score, though.
Meanwhile in Ranchi, in the biggest upset of the tournament so far, Services beat Mumbai by eight wickets by chasing down 265 with 27 balls remaining.
Shubham Rohilla and Ravi Chauhan, the Services openers, hit centuries. Their opening stand of 231 broke the back of the chase. That meant Jaiswal's 104 went in vain and Mumbai, who started their campaign with an eight-wicket win after skittling out Bengal for 121, have one win and one loss in the competition.
Shashank Kishore is a senior sub-editor at ESPNcricinfo