Set an imposing target of 437, the hosts -- last season's Ranji Trophy champions -- were all out for 198 in their second innings on the fifth and final day at the Captain Roop Singh Stadium.
The day once again belonged to Yashasvi Jaiswal, who now has nine hundreds in 15 first-class games. The left-hander's 157 ball knock had 16 fours and three sixes.
Karnataka skipper Mayank Agarwal, the leading run-getter in the recently-concluded Ranji Trophy season, will lead Rest of India in the Irani Cup match against Madhya Pradesh, starting March 1 in Gwalior.
Sen takes five wickets to end Saurashtra’s second-innings resistance before opener Abhimanyu Easwaran hit an unbeaten fifty to seal Rest of India’s eight-wicket win in the Irani Cup with a day to spare.