Tamil Nadu scored 310 and 277 for 6 declared respectively in both their innings, while Assam could muster 134 and 184 in their two knocks.
Tamil Nadu, with four points from this outing, continue to lead Group 'B' with 15 points (including a bonus point) after three wins and two draws. They play Hyderabad in their last 'away' round-robin tie in the seven-team league. For Tamil Nadu, medium pacer Kumaran emerged the chief wicket-taker with 5 for 57.
Needing 454 for victory, Assam, overnight 158 for 6, lost the wicket of Vasanth Saravanan when he snicked Tamil Kumaran to wicketkeeper Dinesh Karthik. Saravanan top-scored with 62 runs, which included ten hits to the fence.
Overnight not out batsman Gautam Dutta, who was shaping well, stepped out to clear medium pacer Ganapathy but hit into the hands of E Suresh, substituting for S Sharath, in the long off region. His 26 came of 25 balls with five fours.
With R Raghuram being clean bowled by Kumaran, the Assam innings ended. Meanwhile, Gujarat beat Rajasthan by six wickets on the fourth and final day of the Ranji Trophy Elite Group B league cricket match in Jaipur.
Gujarat now has 8 points from four matches and may eye semifinal berth but Rajasthan, only four points from as many matches, is out of the race.
For the visitors Niraj Patel scored an unbeaten half-century and while skipper Mukund Parmar hit a useful knock of 41 to reach the target.
Chasing a victory target of 174, Gujarat resumed at their overnight score of 94 for one and started the last day with Patel striking freely but batting with caution, too, to steer them to a six-wicket unexpected victory.
On the first two days the hosts appeared in commanding position as they scored 259 for eight in their first innings and then ripped the Gujarat batsmen through their bowlers restricting them at 188 for nine on the second day.
Earlier, visitors lost Aakash Christian (32) and K Damani (1) but Patel (77) and Parmar batted sensibly to ward off any danger and added 66 for the fourth wicket.
Parmar fell prey to Anup Dave but at that time Gujarat were close to victory. Patel completed his fifty in 128 balls with seven fours and guided his team to 176 for four well before lunch on the last day of the match.