Their knocks helped Andhra wrest the initiative against the star-studded hosts after having been 64 for 5 at one point to end the day at 231 for 7, a lead of 55.
Tamil Nadu had been dismissed for 176 in the first innings yesterday.
Resuming at the overnight score of eight without loss, the visiting side was in trouble almost immediately as opener D B Prashanth Kumar fell to L Vignesh.
Skipper Hanuma Vihari was the next to depart, falling to a catch by BN Aparajith at gully off the bowling of L Vignesh for 3.
K S Bharat and Ricky Bhui began the rescue act but after adding 28 runs before the latter was dismissed by the other Vignesh.
The experienced Y Venugopala Rao didn't last too long as he was caught by Rahil Shah off R Ashwin's bowling for just three.
When Ashwin had Bharat stumped by N Jagadeesan for 32, Andhra looked in trouble at 64 for 5.
Then came a vital moment in the game as M S Washington Sundar dropped Ashwin Hebbar (on 13) off Ashwin's bowling at deep mid-wicket.
The 21-year-old batsman made the most of the life he got and scored runs in an attractive manner.
From 95 for 5 at lunch, Sumanth, who showed great resolve to defy the bowling, took the fight to Tamil Nadu in Hebbar's company.
Sumanth didn't resume his knock after the tea interval owing to a hand injury, but Hebbar kept the scoreboard moving.
He was dismissed by K Vignesh for 64.
Bhargav Bhatt, the team's bowling hero yesterday, was caught behind off Washington Sundar's bowling.
Sumanth, who returned at the fall of Bhatt, took the team to the close without any further damage and swelled the lead to 55 runs.
For Tamil Nadu, K Vignesh, L Vignesh and Ashwin bagged two wickets each.
Test all-rounder Ashwin, who bowled 23 overs, looked dangerous in the first session but couldn't make much of an impression in the post-lunch period.
"I think credit is due to them for the way they batted. I think it could have (the dropped chance of Hebbar) made a difference. Catches being dropped are part of the game and I wouldn't dwell much on it," he told reporters.
Brief scores (End of day 2): Group "C" Tamil Nadu 176 all out (Baba Aparajith 51, K Vignesh 25 not out, Bhargav Bhatt 4 for 52, Prithvi Raj Yarra 3 for 39) vs Andhra Pradesh 231 for 7 (B Sumanth 72 batting, Ashwin Hebbar 64, K S Bharat 32, K Vignesh 2 for 46, L Vignesh 2 for 36, R Ashwin 2 for 51) in Chennai.
Tripura vs Odisha - Play on day two also washed out without a ball being bowled, at Cuttack.
Disclaimer: No Business Standard Journalist was involved in creation of this content
